METHOD FOR TESTING PRESENCE OR ABSENCE OF MYCOPLASMA
20200308633 ยท 2020-10-01
Assignee
Inventors
Cpc classification
C12N15/1017
CHEMISTRY; METALLURGY
C12Q1/04
CHEMISTRY; METALLURGY
International classification
C12N15/10
CHEMISTRY; METALLURGY
Abstract
A method for testing presence or absence of a Mycoplasma in a specimen is disclosed. The method includes: culturing a specimen; extracting a nucleic acid from the cultured specimen and performing amplification of the nucleic acid using a primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma, in which the specimen is a biotechnology-related product or a part thereof.
Claims
1. A method for preparing a sample for testing for the presence or absence of a Mycoplasma in a specimen, comprising culturing a sample from the specimen in a culture medium containing arginine and glucose for Mycoplasma proliferation, wherein the culturing comprises aerobic culturing of a first sample from the specimen and anaerobic culturing of a second sample from the specimen which is different from the first sample, providing the first and second samples for detecting seven species of Mycoplasmas to be applied for nucleic acid amplification.
2. The method of claim 1, wherein the culture medium further comprise Heart infusion broth (HIB) and a yeast extract.
3. The method of claim 1, wherein a time period of the culturing is 3 to 14 days.
4. The method of claim 1, wherein the sensitivity of the Mycoplasma detection is 10cfu/mL.
5. The method of claim 1, wherein the specimen is a biotechnology-related product, regenerative medicine-related product or regenerative medicine product.
6. A method for preparing a sample for testing for the presence or absence of a Mycoplasma in a specimen, comprising culturing a sample of 950 L or less from the specimen in the culture medium containing arginine and glucose for Mycoplasma proliferation, providing the first and second samples for detecting seven species of Mycoplasmas applied for nucleic acid amplification.
7. The method of claim 6, wherein the culture medium further comprise Heart infusion broth (HIB) and a yeast extract.
8. The method of claim 6, wherein a time period of the culturing is 3 to 14 days.
9. The method of claim 8, wherein a time period of the culturing is 9 days
10. The method of claim 6, wherein the sample is 100 L to 500 L.
11. The method of claim 6, wherein the sensitivity of the Mycoplasma detection is 10cfu/mL.
12. The method of claim 6, wherein the specimen is a biotechnology-related product, regenerative medicine-related product or regenerative medicine product.
13. A method for testing for a presence or absence of a Mycoplasma in a specimen, the method comprising: culturing a specimen to obtain a cultured specimen, the specimen being a biotechnology-related product or a part of a biotechnology-related product; extracting a nucleic acid from the cultured specimen; and performing amplification of the nucleic acid using a primer that is specifically selected to amplify a nucleic acid sequence derived from a Mycoplasma.
14. The method according to claim 13, wherein amplification of the nucleic acid is performed by a polymerase chain reaction (PCR) method.
15. The method according to claim 13, wherein the culturing of the specimen comprises culturing two or more specimens each in an aerobic or anaerobic condition.
16. The method according to claim 13, wherein the culturing of the specimen comprises performing cultivation of the specimen for 3 to 14 days.
17. The method according to claim 13, further comprising removing impurities before the extracting of the nucleic acid with a filter.
18. The method according to claim 13, wherein the regenerative medicine-related product includes at least one of (i) a cell subjected to processing, (ii) a cell to be provided to processing, (iii) a reagent to be used in processing or testing, (iv) a culture medium for culturing a cell, (v) a cell washing solution for washing a cell, and/or (vi) a preservation liquid for preserving a regenerative medicine product.
19. A method of managing quality of a biotechnology-related product, the method comprising: testing for presence or absence of a Mycoplasma in a specimen of claim 13.
20. A kit for use in the method according to claim 13, the kit comprising: a culture medium for culturing a Mycoplasma; and a primer specifically selected to amplify a nucleic acid sequence derived from Mycoplasma.
21. The kit according to claim 20, further comprising a filter for removing impurities.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
[0053] Set forth below with reference to the accompanying drawings is a detailed description of embodiments of method for testing the presence or absence of a Mycoplasma representing examples of the method disclosed here.
[0054] Unless defined otherwise in this specification, all technical terms and scientific terms used have the same meanings as usually understood by those skilled in the art. All patents, applications, and other publications or information referred to in this specification are incorporated in this specification by reference in their entireties. Further, if any contradiction arises between publications referred to in this specification and descriptions in this specification, the descriptions in this specification supersede.
[0055] A method for testing the presence or absence of a Mycoplasma in a specimen includes: a step of extracting a nucleic acid from a specimen and performing amplification of the nucleic acid using a primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma.
[0056] As used here, the specimen is not particularly limited and may be any target in which contamination by Mycoplasma is desired to be tested (e.g., a target in which there is a concern of Mycoplasma contamination, a part thereof, or the like). Non-limiting examples of targets include biomedical materials of any biological origin (for example, tissues, cells, biologic fluids, and the like) and products produced using biomedical materials as raw materials (for example, some of organs, fusion cells, pharmaceutical products of biological origin, and the like). Without limitation, specific examples include animal-derived biomedical materials and products produced using these materials as raw materials, and those which are provided for tests or production performed using animal-derived biomedical materials. Examples of the animal-derived biomedical materials and products produced using these materials as raw materials include, but are not limited to, cells, tissues, blood (whole blood or some of whole blood, for example, including serum, blood plasma, and the like), placenta, urine, and antibodies of animals, biological preparations (for example, proteins, polypeptide, derivatives thereof, and pharmaceutical products, antibody pharmaceutical products, vaccines, antitoxins, blood preparations, and the like which use proteins, polypeptide, or derivatives thereof as constituents), and regenerative medicine products. Examples of those which are provided for tests or production performed using animal-derived biomedical materials include, but are not limited to, tools which are provided for tests or production performed using animal-derived biomedical materials (for example, cell culture vessels and the like), reagents, serum, antibodies, culture media, and washing solutions.
[0057] Further, the specimen as used here may be those which are produced as a biotechnology-related product or a regenerative medicine-related product.
[0058] As used here, the biotechnology-related product includes a biological preparation, a regenerative medicine product, or a product and the like which are used in production thereof.
[0059] As used here, the biological preparation includes, for example, proteins, polypeptide, derivatives thereof, and pharmaceutical products, antibody pharmaceutical products, vaccines, antitoxins, blood preparations, and the like which use proteins, polypeptide, or derivatives thereof as constituents.
[0060] As used here, a product used in production of a biological preparation includes a cell producing a recombination protein or a polypeptide, blood (whole blood or some of whole blood, for example, including serum, blood plasma, and the like), placenta, urine, a culture medium for culturing a cell, a cell washing solution for washing a cell, a preservation liquid for preserving a biological preparation, a reagent to be used in processing or testing (for example, a buffer solution, a detection reagent, serum, a growth factor, an yeast extract, or the like), and the like.
[0061] Examples of the cell producing a recombination protein or a polypeptide include E. coli, yeast, insect cells, plant cells, hybridoma, animal cells (for example, CHO cells, Sp2/0 cells, NSO cells, and the like), and human cells. In an aspect of methods described herein, the product used in production of a biological preparation can include a vaccine, but the vaccine can also be excluded from the product used in production of a biological preparation.
[0062] As used here, the regenerative medicine-related product includes a regenerative medicine product or a product and the like which are used in production of the regenerative medicine product.
[0063] As used here, the regenerative medicine product is (1) a product which is obtained by subjecting cells of humans or animals to processing such as cultivation, and which (a) reconstructs/restores/forms a structure/function of a body or (b) is used for medical treatment/prevention of diseases, or is (2) a product which is introduced into cells of a human and then used for the purpose of gene therapy. The regenerative medicine product includes a cell used in medical treatment as a body, and for example, includes a cell subjected to processing and a cell to be provided to processing. Specifically, non-limiting examples thereof include human (allogeneic) bone marrow-derived mesenchymal stem cells used in medical treatment of acute graft-versus-host disease (acute GVHD) after hematopoietic stem cell transplantation, human (autologous) skeletal muscle-derived cell sheets to be transplanted in medical treatment of serious heart failures, and cells to be used in cancer immunotherapy (such as dendritic cells, NK cells, and T lymphocytes).
[0064] As used here, a product used in production of the regenerative medicine product includes a reagent to be used in processing or testing (for example, a buffer solution, a detection reagent, serum, a growth factor, an yeast extract, or the like) a culture medium for culturing a cell, a cell washing solution for washing a cell, a preservation liquid for preserving a regenerative medicine product, and the like.
[0065] As used here, the cell subjected to processing and the cell to be provided to processing are animal cells, preferably mammal cells, and more preferably human cells.
[0066] Non-limiting examples of the cell subjected to processing and the cell to be provided to processing include somatic cells (for example, myocardial cells, fibroblasts, epithelial cells, endothelial cells, hepatic cells, pancreatic cells, renal cells, adrenal cells, periodontal ligament cells, gingival cells, periosteal cells, skin cells, synovial cells, cartilage cells, dendritic cells, lymphocytes (natural killer (NK) cells, T lymphocytes, and B lymphocytes), and the like), and stem cells (for example, tissue stem cells such as myoblasts and cardiac stem cells, embryonic stem cells (ES) cells), pluripotent stem cells such as induced pluripotent stem (iPS) cells, mesenchymal stem cells, and the like). The somatic cells may be stem cells, in particular, cells differentiated from iPS cells, and specific examples thereof include iPS-derived myocardial cells, iPS-derived dendritic cells, and iPS-derived lymphocytes (NK cells, T lymphocytes, and B lymphocytes). These cells may be modified by gene introduction, and specific examples of such cells include a chimeric antigen receptor-T cell (CAR-T) and a T cell receptor-T cell (TCR-T).
[0067] The cell subjected to processing refers to a cell obtainable after being subjected to some kind of processing, and the cell to be provided to processing refers to a cell to be prepared before being subjected to processing. The processing is not limited, and may be any operation applied to cells, and for example, may be processing for treatment of diseases. Specific examples of such cells include cells cultured in a liquid, cells cultured in the environment, for example, in a gel, cell cultures cultured and then three-dimensionally constructed via cellular adhesion, sheet-shaped cell cultures, cell suspensions in which a cell density is adjusted, cells cultured and grown, cells cultured and provided to freezing, cells melted from a freeze state, cells in which the number of cells or density thereof is adjusted, and cells to be set for administration in an administration device.
[0068] Diseases to be treated by such cells are not limited, and examples thereof include cardiac diseases, lung diseases, liver diseases, pancreatic disorders, kidney diseases, large intestine diseases, small intestine diseases, spinal cord diseases, central nervous system diseases, bone diseases, eye diseases, and skin diseases. Cancers (malignant neoplasm) such as blood cancer and solid cancer are included in diseases. In a case where cells to be used are myoblasts or (iPS-derived) myocardial cells, examples of diseases include cardiac infarction (including chronic cardiac failure accompanied by cardiac infarction), dilated cardiomyopathy, ischemic cardiomyopathy, and cardiac diseases (for example, cardiac failure, particularly chronic cardiac failure) accompanied by systolic functional disorder (for example, left systolic functional disorder).
[0069] In an embodiment, the regenerative medicine-related product includes at least one cell which either has been or will be subjected to processing or provided to processing, a reagent to be used in processing or testing, a culture medium for culturing a cell, a cell washing solution for washing a cell, and a preservation liquid for preserving a regenerative medicine product. Specific examples include, but are not limited to, a sheet-shaped cell culture, a cell for producing a sheet-shaped cell culture (for example, a cryopreserved cell or the like), a sheet preparation culture medium, and a cell washing solution.
[0070] In an embodiment, the regenerative medicine-related product includes at least one selected from a cell subjected to processing and/or a cell to be provided to processing.
[0071] In an embodiment, the regenerative medicine-related product includes at least one selected from myoblasts and iPS-derived myocardial cells.
[0072] In an embodiment, the regenerative medicine-related product includes at least one mesenchymal stem cell and/or fibroblast.
[0073] In an embodiment, the regenerative medicine-related product includes at least one dendritic cell, NK cell, T lymphocyte, B lymphocyte, CAR-T, and/or TCR-T.
[0074] As used here, the sheet-shaped cell culture refers to cells linked together into the shape of a sheet. Cells may be linked together directly (including cellular adhesion linked via cellular elements, such as adhesion molecules) and/or linked together via an intervening substance. The intervening substance is not particularly limited as long as it is a substance having at least an ability to physically (mechanically) link cells together, and examples thereof include extracellular matrices. The intervening substance may be a substance derived from cells, in particular, a substance derived from cells constituting the cell culture. Although the cells are linked at least physically (mechanically), the cells may be further linked functionally, for example, chemically or electrically. The sheet-shaped cell culture may be a culture configured with a single cell layer (single layer), or a culture configured with two or more cell layers (stacked (multilayer) architecture, for example, two layers, three layers, four layers, five layers, six layers, and the like).
[0075] The sheet-shaped cell culture is used in medical treatment of humans or animals, and cells constituting the sheet-shaped cell culture may be animal cells, preferably mammal cells, and more preferably human cells.
[0076] The cells constituting the sheet-shaped cell culture are not particularly limited as long as they can form the sheet-shaped cell culture, and for example, include adhesion cells (adherent cells). Examples of suitable adhesion cells include, but are not limited to, adherent somatic cells (for example, myocardial cells, fibroblasts, epithelial cells, endothelial cells, hepatic cells, pancreatic cells, renal cells, adrenal cells, periodontal ligament cells, gingival cells, periosteal cells, skin cells, synovial cells, cartilage cells, and the like) and stem cells (for example, tissue stem cells such as myoblasts and cardiac stem cells, embryonic stem cells, pluripotent stem cells such as induced pluripotent stem (iPS) cells, mesenchymal stem cells, and the like). The somatic cells may be stem cells, such as cells differentiated from iPS cells.
[0077] Further, non-limiting examples of the cells constituting the sheet-shaped cell culture include myoblasts (for example, skeletal myoblasts and the like), mesenchymal stem cells (for example, bone marrow, adipose tissue, peripheral blood, skin, hair root, muscular tissue, endometrium, placenta, cord blood-derived cells, and the like), myocardial cells, fibroblasts, cardiac stem cells, embryonic stem cells, iPS cells, synovial cells, cartilage cells, epithelium cells (for example, oral mucosaepithelium cells, retinal pigment epithelial cells, nasal epithelial cells, and the like), endothelial cells (for example, vascular endothelial cells and the like), hepatocytes (for example, hepatic parenchymal cells and the like), pancreatic cells (for example, islet cells and the like), renal cells, adrenal gland cells, human periodontal ligament cells, gingiva cells, periosteum cells, and skin cells. The sheet-shaped cell culture is configured by these cells, and specific examples thereof include a skeletal myoblast sheet, an iPS-derived myocardial cell sheet, a mesenchymal stem cell sheet, and a fibroblast sheet.
[0078] The Mycoplasma is not particularly limited as long as it is a bacterium classified in the class Mollicutes. Examples include, but are not limited to, bacteria belonging to the genus Mycoplasma in the family Mycoplasmataceae, the genus Acholeplasma in the family Acholeplasmataceae, the genus Spiroplasma in the family Spiroplasmataceae, and the like. More specific examples thereof include Mycoplasma arginini, Mycoplasma salivarium, Mycoplasma pneumoniae, Mycoplasma fermentans, Mycoplasma orale, Mycoplasma hyorhinis, Mycoplasma synoviae, Acholeplasma laidlawii, and Spiroplasma citri. In this specification, Mycoplasma arginini is also referred to as Ma, Mycoplasma salivarium is also referred to as Ms, Mycoplasma pneumoniae is also referred to as Mp, Mycoplasma fermentans is also referred to as Mf, Mycoplasma orale is also referred to as Mo, Mycoplasma hyorhinis is also referred to as Mh, and Acholeplasma laidlawii is also referred to as Al.
[0079] It is sufficient that the amount of a specimen is an amount necessary for amplifying a Mycoplasma to an amount beyond the detection sensitivity of this method, and it is possible for those having ordinary knowledge in the relevant technical field to set an appropriate amount. Non-limiting examples thereof include 10 L, 15 L, 20 L, 25 L, 30 L, 35 L, 40 L, 45 L, 50 L, 55 L, 60 L, 65 L, 70 L, 75 L, 80 L, 85 L, 90 L, 95 L, 100 L, 110 L, 120 L, 130 L, 140 L, 150 L, 160 L, 170 L, 180 L, 190 L, 200 L, 250 L, 300 L, 350 L, 400 L, 450 L, 500 L, 550 L, 600 L, 650 L, 700 L, 750 L, 800 L, 850 L, 900 L, 950 L, 1 mL, 2 mL, 3 mL, 4 mL, 5 mL, 6 mL, 7 mL, 8 mL, 9 mL, and 10 mL.
[0080] The lower limit of the amount of a specimen is not particularly limited as long as it is an amount necessary for amplifying a Mycoplasma to an amount beyond the detection sensitivity of this method. Non-limiting examples thereof include 10 L or more, 15 L or more, 20 L or more, 25 L or more, 30 L or more, 35 L or more, 40 L or more, 45 L or more, 50 L or more, 55 L or more, 60 L or more, 65 L or more, 70 L or more, 75 L or more, 80 L or more, 85 L or more, 90 L or more, 95 L or more, and 100 L or more. In certain embodiments, the amount of a specimen is 100 L.
[0081] The upper limit of the amount of a specimen is not particularly limited, but in the case of the method described here, in a regenerative medicine-related product, among amounts in which the detection sensitivity of this method can be achieved, the amount is preferably an amount as small as possible. Non-limiting examples thereof include 10 mL or less, 9 mL or less, 8 mL or less, 7 mL or less, 6 mL or less, 5 mL or less, 4 mL or less, 3 mL or less, 2 mL or less, 1 mL or less, 950 L or less, 900 L or less, 850 L or less, 800 L or less, 750 L or less, 700 L or less, 650 L or less, 600 L or less, 550 L or less, 500 L or less, 450 L or less, 400 L or less, 350 L or less, 300 L or less, 250 L or less, 200 L or less, 150 L or less, and 100 L or less.
[0082] As for the range of the amount of a specimen, combinations of the upper limits and the lower limits exemplified above are mentioned. That is, examples thereof include 10 L to 10 mL, 10 L to 9 mL, 10 L to 8 mL, 10 L to 7 mL, 10 L to 6 mL, 10 L to 5 mL, 10 L to 4 mL, 10 L to 3 mL, 10 L to 2 mL, 10 L to 1 mL, 10 to 900 L, 10 to 800 L, 10 to 700 L, 10 to 600 L, 10 to 500 L, 10 to 400 L, 10 to 300 L, 10 to 200 L, 10 to 100 L, 100 L to 10 mL, 100 L to 9 mL, 100 L to 8 mL, 100 L to 7 mL, 100 L to 6 mL, 100 L to 5 mL, 100 L to 4 mL, 100 L to 3 mL, 100 L to 2 mL, 100 L to 1 mL, 100 to 900 L, 100 to 800 L, 100 to 700 L, 100 to 600 L, 100 to 500 L, 100 to 400 L, 100 to 300 L, and 100 to 200 L. The range thereof is particularly preferably 100 to 1000 L and further preferably 100 to 500 L.
[0083] The nucleic acid is DNA or RNA, and is preferably DNA.
[0084] The method of extracting a nucleic acid from a specimen is not particularly limited as long as it can extract a nucleic acid of a Mycoplasma, and it is possible for those skilled in the art to appropriately select an optimal method. For example, phenol/chloroform extraction, an extraction method using a carrier, and the like may be employed. Extraction of a nucleic acid may be performed using a commercially available kit for nucleic acid extraction.
[0085] The method of amplifying a nucleic acid is not particularly limited as long as it can amplify a nucleic acid sequence derived from a Mycoplasma, and it is possible for those skilled in the art to appropriately select an optimal method.
[0086] Examples of the method of amplifying a nucleic acid include a polymerase chain reaction (PCR) method and a loop-mediated isothermal amplification (LAMP) method.
[0087] The step of performing amplification of the nucleic acid is performed by a polymerase chain reaction (PCR) method. In the PCR method, a primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma, polymerase, a buffer, PCR conditions (temperature, time, the number of cycles, and the like), and the like can be appropriately selected.
[0088] PCR may be, for example, regular PCR, real-time PCR, Nested PCR, reverse transcription PCR, or the like. Regular PCR is preferred.
[0089] As described above, as for the primer used here, any primers may be used as long as they can amplify a nucleic acid sequence derived from a Mycoplasma. Non-limiting examples of the primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma include the following sequences:
TABLE-US-00001 Forward: (SEQIDNO:1) 5-GGCGAATGGGTGAGTAACACG-3, and Reverse: (SEQIDNO:2) 5-CGGATAACGCTTGCGACCTATG-3.
[0090] A method for testing presence or absence of a Mycoplasma in a specimen described here comprises: [0091] (a) a step of culturing a specimen; and [0092] (b) a step of extracting a nucleic acid from the cultured specimen and performing amplification of the nucleic acid using a primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma ,
in which the specimen is a biotechnology-related product or a part thereof.
[0093] In an embodiment, the specimen is a regenerative medicine-related product or a part thereof.
[0094] In an embodiment, the regenerative medicine-related product includes at least one cell subjected to processing or cell to be provided to processing, a reagent to be used in processing or testing, a culture medium for culturing a cell, a cell washing solution for washing a cell, and a preservation liquid for preserving a regenerative medicine product. Specific examples thereof include a sheet-shaped cell culture, a cell for producing a sheet-shaped cell culture (for example, a cryopreserved cell or the like), a sheet preparation culture medium, and a cell washing solution.
[0095] In an embodiment, this method further includes (c) performing electrophoresis of an amplified PCR product obtained from (b).
[0096] The electrophoresis of the amplified product is not particularly limited as long as it is a method with which the amplified nucleic acid can be detected, and it is possible for those skilled in the art to appropriately select an optimal method. For example, as for a method for preparing a gel such as agarose gel, selection of a buffer, and a method of checking a band, it is possible for those skilled in the art to appropriately select an optimal method. Examples of the method of checking a band include staining of a nucleic acid with ethidium bromide, SYBR (registered trademark) Green, or the like and a southern blotting method.
[0097] In the methods disclosed here, conditions of the cultivation are not particularly limited as long as a method can amplify a Mycoplasma, and it is possible for those skilled in the art to appropriately select an optimal method. For example, types and composition of a culture medium, a cultivation temperature, an atmosphere, a CO.sub.2 concentration, and the like can also be appropriately selected.
[0098] In the methods disclosed here, cultivation may be performed by aerobic cultivation or anaerobic cultivation and can be appropriately selected according to types of a Mycoplasma to be tested. For example, as for five kinds of Mycoplasma arginini, Mycoplasma pneumoniae, Mycoplasma fermentans, Mycoplasma orale, and Acholeplasma laidlawii, these Mycoplasmas can be amplified under any of an aerobic condition and an anaerobic condition; however, since Mycoplasma salivarium can be amplified only under an anaerobic condition and Mycoplasma hyorhinis can be amplified only under an aerobic condition, six kinds other than Mycoplasma salivarium may be cultured under an aerobic condition and Mycoplasma salivarium may be cultured under an anaerobic condition. In order to perform testing of all seven kinds, two or more specimens can be each cultured in an aerobic or anaerobic condition.
[0099] In an embodiment, this method includes performing anaerobic cultivation in (a).
[0100] In an embodiment, in this method, two or more specimens are each cultured in an aerobic or anaerobic condition.
[0101] In an embodiment, an amount of a specimen to be cultured in (a) is 10 L to 10 mL.
[0102] In an embodiment, an amount of a specimen to be cultured in (a) is 100 L to 1 mL.
[0103] In an embodiment, an amount of a specimen to be cultured in (a) is 100 L to 500 L.
[0104] The period of time for cultivation may be a period which is sufficient for amplifying a Mycoplasma to an amount beyond the detection sensitivity obtained by this method, and can be arbitrarily set. Non-limiting examples of the period of time for cultivation include 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, and 14 days. Non-limiting examples of the range of the period of time for cultivation include 1 day to 14 days, 1 day to 7 days, 3 days to 14 days, 3 days to 7 days, and 6 days to 10 days. The time period range is preferably 3 days to 14 days and more preferably 6 days to 10 days.
[0105] In an embodiment, cultivation is performed for 6 days to 10 days.
[0106] Further, in an embodiment, cultivation is performed for 3 days to 7 days.
[0107] In an embodiment, the method further includes removing impurities before the nucleic acid is extracted in (b).
[0108] The impurities are, for example, substances other than bacteria of Mycoplasmas, and specifically, are nucleic acids, proteins, and the like, and are preferably nucleic acid fragments of Mycoplasma s.
[0109] As for removal of the impurities, a method with which impurities decrease as compared with the case before removal is sufficient. Examples of the method of removing impurities include a method of filtering or collecting a specimen by a filter and a method of performing harvest by centrifugal separation.
[0110] The impurities may pass through a filter so as to be removed or may remain on a filter without passing through a filter so as to be removed. Preferably, the impurities pass through a filter so as to be removed.
[0111] In an embodiment, removal of the impurities is performed by collecting the specimen with a filter.
[0112] As for the filter for collection, a commercially available filter can be used. The pore size of the filter is, for example, 0.22 m, 0.1 m, 0.01 m, and 0.005 m. For example, in the case of a filter having a pore size of 0.1 m, a substance having a size of about 0.1 m, for example, a virus or the like can be trapped. The filter may be a filter which is designed to exclude impurities having a specific molecular weight, and for example, the molecular weight cutoff (MWCO) of the filter is 1000 kDa, 100 kDa, and 50 kDa. For example, the filter having a molecular weight cutoff of 100 kDa is a filter which can trap a substance having a size of about 100 kDa. The molecular weight cutoff of the filter is 50 to 1000 kDa and preferably 50 to 100 kDa.
[0113] Impurities may be smaller than the molecular weight cutoff of the filter and be allowed to pass through the filter so as to be removed, or may be larger than the molecular weight cutoff of the filter and remain on the filter without being allowed to pass through the filter so as to be removed. Preferably, impurities are smaller than the molecular weight cutoff of the filter and pass through the filter.
[0114] A molecular weight cutoff of a filter is 1000 kDa or less or a pore size of a filter is 0.22 m or less.
[0115] In an embodiment, a molecular weight cutoff of a filter is 100 kDa or less.
[0116] An aspect of the disclosure here relates to a method of managing quality of a biotechnology-related product, the method including testing presence or absence of a Mycoplasma in a specimen by the method described herein.
[0117] An aspect of the disclosure relates to a method of managing quality of a regenerative medicine-related product, the method including testing presence or absence of a Mycoplasma in a specimen by the method described herein.
[0118] A method disclosed here for testing the presence or absence of a Mycoplasma in a specimen involves: [0119] (i) a step of removing impurities from a composition containing a specimen; and [0120] (ii) a step of extracting a nucleic acid from the composition containing a specimen from which impurities have been removed and performing amplification of the nucleic acid using a primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma.
[0121] The composition containing a specimen is, for example, a composition containing a culture medium, a reagent, or the like, which is used for testing presence or absence of a Mycoplasma, in addition to a specimen.
[0122] Impurities are, for example, substances other than bacteria of Mycoplasmas, and specifically, are nucleic acids, proteins, and the like, and are preferably nucleic acid fragments of Mycoplasma s.
[0123] As for removal of the impurities, a method with which impurities decrease as compared with the case before removal is sufficient. Examples of the method of removing impurities include a method of filtering or collecting a specimen by a filter and a method of performing harvest by centrifugal separation.
[0124] The impurities may pass through a filter so as to be removed or may remain on a filter without passing through a filter so as to be removed. Preferably, the impurities pass through a filter so as to be removed.
[0125] In the step (i), the step of removing impurities is performed by collecting the specimen with a filter.
[0126] As for the filter for collection, a commercially available filter can be used. The pore size of the filter is, for example, 0.22 m, 0.1 m, 0.01 m, and 0.005 m. For example, in the case of a filter having a pore size of 0.1 m, a substance having a size of about 0.1 m, for example, a virus or the like can be trapped. The filter may be a filter which is designed to exclude impurities having a specific molecular weight, and for example, the molecular weight cutoff (MWCO) of the filter is 1000 kDa, 100 kDa, and 50 kDa. For example and without limitation, the filter having a molecular weight cutoff of 100 kDa may be a filter which can trap a substance having a size of about 100 kDa. In certain embodiments, the molecular weight cutoff of the filter is 50 to 1000 kDa and preferably 50 to 100 kDa.
[0127] Impurities may be smaller than the molecular weight cutoff of the filter and be allowed to pass through the filter so as to be removed, or may be larger than the molecular weight cutoff of the filter and remain on the filter without being allowed to pass through the filter so as to be removed. Preferably, impurities are smaller than the molecular weight cutoff of the filter and pass through the filter.
[0128] A molecular weight cutoff of a filter is 1000 kDa or less or a pore size of a filter is 0.22 m or less.
[0129] A molecular weight cutoff of a filter is 100 kDa or less.
[0130] This method further includes (iii) a step of performing electrophoresis of an amplified product obtained from the step (ii).
[0131] The electrophoresis of the amplified product is not particularly limited as long as it is a method with which the amplified nucleic acid can be detected, and it is possible for those skilled in the art to appropriately select an optimal method. For example, as for a method for preparing a gel such as agarose gel, selection of a buffer, and a method of checking a band, it is possible for those skilled in the art to appropriately select an optimal method. Examples of the method of checking a band include staining of a nucleic acid with ethidium bromide, SYBR (registered trademark) Green, or the like and a southern blotting method.
[0132] Conditions of the cultivation are not particularly limited as long as a method can amplify a Mycoplasma, and it is possible for those skilled in the art to appropriately select an optimal method. For example, types and composition of a culture medium, a cultivation temperature, an atmosphere, a CO.sub.2 concentration, and the like can also be appropriately selected.
[0133] Cultivation may be performed by aerobic cultivation or anaerobic cultivation and can be appropriately selected according to types of a Mycoplasma to be tested.
[0134] For example, as for five kinds of Mycoplasma arginini, Mycoplasma pneumoniae, Mycoplasma fermentans, Mycoplasma orale, and Acholeplasma laidlawii, these Mycoplasmas can be amplified under any of an aerobic condition and an anaerobic condition; however, since Mycoplasma salivarium can be amplified only under an anaerobic condition and Mycoplasma hyorhinis can be amplified only under an aerobic condition, six kinds other than Mycoplasma salivarium may be cultured under an aerobic condition and Mycoplasma salivarium may be cultured under an anaerobic condition. In order to perform testing of all seven kinds, two or more specimens can be each cultured in an aerobic or anaerobic condition.
[0135] In an embodiment, the method includes culturing the specimen before (ii).
[0136] In an embodiment, the method includes culturing the specimen before (i).
[0137] The period of time for cultivation may be a period which is sufficient for amplifying a Mycoplasma to an amount beyond the detection sensitivity obtained by this method, and can be arbitrarily set. Non-limiting examples of the period of time for cultivation include 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, and 14 days. Non-limiting examples of the range of the period of time for cultivation include 1 day to 14 days, 1 day to 7 days, 3 days to 14 days, 3 days to 7 days, and 6 days to 10 days. The time period range is preferably 3 days to 14 days and more preferably 6 days to 10 days.
[0138] In an embodiment, the specimen is a biotechnology-related product or a part thereof.
[0139] In an embodiment, the specimen is a regenerative medicine-related product or a part thereof.
[0140] In an embodiment, the regenerative medicine-related product includes at least one selected from a cell subjected to processing, a cell to be provided to processing, a reagent to be used in processing or testing, a culture medium for culturing a cell, a cell washing solution for washing a cell, and a preservation liquid for preserving a regenerative medicine product. Specific examples thereof include a sheet-shaped cell culture, a cell for producing a sheet-shaped cell culture (for example, a cryopreserved cell or the like), a sheet preparation culture medium, and a cell washing solution.
[0141] An aspect of the disclosure here involves a method of managing quality of a biotechnology-related product, the method including a step of testing presence or absence of a Mycoplasma in a specimen by a method described herein.
[0142] An aspect of the disclosure here involves a method of managing quality of a regenerative medicine-related product, the method including a step of testing presence or absence of a Mycoplasma in a specimen by a method described herein.
[0143] Another aspect of the disclosure here involves a kit for use in the method for testing for the presence or absence of a Mycoplasma, the kit including a primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma.
[0144] In an embodiment, the kit includes, in addition to the primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma, a culture medium for culturing a Mycoplasma and/or a filter for removing impurities.
[0145] In an embodiment, the kit may further include, for example, a tool for culturing a Mycoplasma, a reagent or tool used in extraction of a nucleic acid, a reagent used in amplification of a nucleic acid, other tools, and instructions relating to a usage method.
[0146] Examples of the tool for culturing a Mycoplasma include a plate and a tube. Examples of the tool or reagent used in extraction of a nucleic acid include a reagent containing phenol, chloroform, isopropanol, ethanol, PEG, or the like, a column filled with silica beads or a silica membrane, and an anion-exchange column. Examples of the reagent used in amplification of a nucleic acid include polymerase, dNTP, and a buffer. Examples of the other tools include a pipette, a dropper, tweezers, and a tube. Examples of the instructions relating to a usage method include instructions for use and a medium on which information indicating a production method or a usage method, such as a flexible disk, a CD, a DVD, a Blu-ray Disc, a memory card, or an USB memory.
[0147] In an embodiment, the kit includes a culture medium for culturing a Mycoplasma and a primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma.
[0148] In an embodiment, the kit includes a primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma and a filter for removing impurities.
[0149] In an embodiment, the kit includes a culture medium for culturing a Mycoplasma, a primer capable of amplifying a nucleic acid sequence derived from a Mycoplasma, and a filter for removing impurities.
[0150] The methods and other aspects disclosed here will be described in more detail with reference to the following examples; however, these are examples and the present invention is not limited thereto.
Examples
[0151] I. Material
[0152] 1. Mycoplasma Strain
[0153] The following seven kinds of Mycoplasmas were used based on The Japanese Pharmacopoeia 17th Edition (JP17) General Information. Incidentally, all kinds thereof were available from public storage institute and those which had been passaged five times or less were used.
[0154] Mycoplasma arginini ATCC23838
[0155] Mycoplasma salivarium NBRC14478
[0156] Mycoplasma pneumoniae NBRC14401
[0157] Mycoplasma fermentans NBRC14854
[0158] Mycoplasma orale NBRC14477
[0159] Mycoplasma hyorhinis NBRC14858
[0160] Acholeplasma laidlawii NBRC14400
[0161] 2. Liquid Culture Medium for Mycoplasma Detection Test
[0162] Heart Infusion Broth, glucose, arginine hydrochloride, and phenol red were mixed so as to be 18.75 g/L, 3.0 g/L, 3.0 g/L, and 0.025 g/L at a final concentration, respectively, and then autoclave sterilization was performed at 121 C. for 15 minutes. A horse serum, a yeast extract, and potassium penicillin G were added thereto so as to be 15%, 10%, and 250,000 units/L at a final concentration, respectively.
[0163] 3. Agar Medium for Mycoplasma Amplification
[0164] Heart Infusion Broth and agar were mixed so as to be 17.5 g/L and 10 g/L at a final concentration, respectively, and then autoclave sterilization was performed at 121 C. for 15 minutes. A horse serum and a yeast extract were added thereto so as to be 20% and 10% at a final concentration, respectively.
[0165] 4. Specimen
[0166] As for the specimen, cryopreserved cells, a sheet preparation culture medium, and a cell washing solution were used. The cryopreserved cells were cells obtained by suspending skeletal myoblasts in a cryopreservation liquid in a concentration of 3.010.sup.7 cells/mL and then freezing the suspended cells. In the following experiment, cryopreserved cells, which were gently shaken up in a water bath set at 37.0 C. and then melted, were provided to the test. The sheet preparation culture medium was obtained by mixing a DMEM/F12 culture medium and human-derived serum in an amount of 20% (v/v). The cell washing solution was obtained by mixing a Hanks' buffered saline solution (HBSS(-)) and human serum albumin in an amount of 0.5% (v/v). Hereinafter, the cryopreserved cells are also simply referred to as the cells, the sheet preparation culture medium is also simply referred to as the culture medium, and the cell washing solution is also simply referred to as the washing solution.
[0167] II. Method and result
[0168] 1. Setting of Impurity Removing Step
[0169] 100 L of cells, which had been checked that live Mycoplasmas were not mixed, were added as a negative control to 2 mL of a liquid culture medium for a Mycoplasma detection test, and then subjected to aerobic cultivation for 7 days under the conditions of 36 C. and 5% CO.sub.2. Further, as a positive control, one obtained by adding 100 L of cells and 10 L of a Mycoplasma diluent containing 7500 cfu/L of Acholeplasma laidlawii to 2 mL of a liquid culture medium for a Mycoplasma detection test was subjected to aerobic cultivation.
[0170] DNA extraction was performed by using MagNA Pure LC DNA Isolation Kit-Large Volume (Roche) to finally obtain a 200 L DNA extract. 90 L of PCR reaction solution (Takara Ex taq) was added to 10 L of the DNA extract and PCR was performed. As for PCR, PCR was performed for one cycle of 5 minutes at 40 C., one cycle of 10 minutes at 94 C., 20 cycles of 30 seconds at 94 C., 30 seconds at 70 C., and 45 seconds at 72 C. (the part at 70 C. decreases by 1 C. per two cycles, up to 61 C.), 25 cycles of 30 seconds at 94 C., 30 seconds at 60 C., and 45 seconds at 72 C., and one cycle of 4 minutes at 72 C. As for the primer, the following sequences were used.
[0171] Primer sequences:
TABLE-US-00002 Forward: (SEQIDNO:1) 5-GGCGAATGGGTGAGTAACACG-3 Reverse: (SEQIDNO:2) 5-CGGATAACGCTTGCGACCTATG-3
[0172] The reaction solution after PCR was subjected to electrophoresis with an agarose gel, and then the presence or absence of a DNA band was checked.
[0173] The result is shown in
[0174] In order to remove the nucleic acid fragments of the Mycoplasma from the test system, trapping of the Mycoplasma by a centrifugal ultrafiltration filter was examined.
[0175] 100 L of cells, which had been checked that live Mycoplasmas were not mixed, were added as a negative control to 2 mL of a liquid culture medium for a Mycoplasma detection test, and then subjected to aerobic cultivation for 7 days under the conditions of 36 C. and 5% CO.sub.2. Further, as a positive control, one obtained by adding 100 L of cells and 10 L of a Mycoplasma diluent containing 7500 cfu/L of Acholeplasma laidlawii to 2 mL of a liquid culture medium for a Mycoplasma detection test was subjected to aerobic cultivation.
[0176] 500 L of the supernatant subjected to centrifugation for 5 minutes at 4 C. and 400g was transferred to a centrifugal ultrafiltration filter (Merck Millipore, Am icon Ultra 100 kDa) having a molecular weight cutoff of 100 kDa and then subjected to centrifugation for 10 minutes at 4 C. and 14,000g. 500 L of PBS was added thereto and subjected to centrifugation for 10 minutes at 4 C. and 14,000g, 500 L of PBS was then further added and subjected to vigorously pipetting, and the solution was recovered. The reaction solution after PCR was subjected to electrophoresis with an agarose gel and then the presence or absence of a DNA band was checked.
[0177] The result is shown in
[0178] 2. Selection of Filter
[0179] A centrifugal ultrafiltration filter for trapping a Mycoplasma was examined. As for the centrifugal ultrafiltration filter, three types of a centrifugal ultrafiltration filter having a molecular weight cutoff of 100 kDa (Merck Millipore, Am icon Ultra 100 kDa), a centrifugal ultrafiltration filter having a pore size of 0.1 m (Merck Millipore, Ultrafree 0.1 m), and a centrifugal ultrafiltration filter having a pore size of 0.22 m (Merck Millipore, Ultrafree 0.22 m) were used, and as for the Mycoplasma, Mycoplasma pneumoniae and Acholeplasma laidlawii were used. As the specimen, a cell, a culture medium, and a washing solution were used. In a case where the specimen is a cell, 2000 L of a liquid culture medium for a Mycoplasma detection test, 100 L of a specimen, and 100 L of 20000 cfu/mL Mycoplasma diluent were added. 500 L of the supernatant subjected to centrifugation for 5 minutes at 4 C. and 400g was transferred to a filter and then subjected to centrifugation for 10 minutes at 4 C. and 14,000g. In a case where the specimen is a culture medium or a washing solution, 2000 L of a liquid culture medium for a Mycoplasma detection test, 500 L of a specimen, and 100 L of 20000 cfu/mL Mycoplasma diluent were added. 500 L was transferred to a filter and then subjected to centrifugation for 10 minutes at 4 C. and 14,000g. 500 L of PBS was added thereto and subjected to centrifugation for 10 minutes at 4 C. and 14,000g, 500 L of PBS was then further added and subjected to vigorously pipetting, and the Mycoplasma trapped with the filter was recovered. As a negative control, the same operation was performed in the condition without addition of a Mycoplasma diluent.
[0180] DNA was extracted from the filter-recovered liquid by using MagNA Pure LC DNA Isolation Kit-Large Volume (Roche) to finally obtain a 200 L DNA extract.
[0181] 10 L of the DNA extract was added to 90 L of PCR reaction solution (Takara Ex taq), and PCR was performed for one cycle of 5 minutes at 40 C., one cycle of 10 minutes at 94 C., 20 cycles of 30 seconds at 94 C., 30 seconds at 70 C., and 45 seconds at 72 C. (the part at 70 C. decreases by 1 C. per two cycles, up to 61 C.), 25 cycles of 30 seconds at 94 C., 30 seconds at 60 C., and 45 seconds at 72 C., and one cycle of 4 minutes at 72 C. As for the primer, the following sequences were used.
[0182] Primer sequences:
TABLE-US-00003 Forward: (SEQIDNO:1) 5-GGCGAATGGGTGAGTAACACG-3 Reverse: (SEQIDNO:2) 5-CGGATAACGCTTGCGACCTATG-3
[0183] The reaction solution after PCR was subjected to electrophoresis with an agarose gel, and then the presence or absence of a DNA band was checked. A case where a DNA band of the Mycoplasma can be confirmed in the filter-recovered liquid was determined that the Mycoplasma can be trapped. The results are shown in Table 1. As for Mycoplasma pneumoniae, the Mycoplasma was able to be trapped in any specimens with a filter having a pore size of 0.22 m. As for Acholeplasma laidlawii, the Mycoplasma was able to be trapped in the washing solution specimen with a filter having a pore size of 0.22 m, the Mycoplasma was able to be trapped in the culture medium specimen with a filter having a pore size of 0.1 m, and the Mycoplasma was able to be trapped in the cellular specimen with a filter having a molecular weight cutoff of 100 kDa. In all the specimens, only in the case of using a filter having a molecular weight cutoff of 100 kDa, two kinds of Mycoplasmas were able to be trapped.
[Table 1]
[0184]
TABLE-US-00004 TABLE 1 Trapping possibility of mycoplasma in each filter Nega- tive Acholeplassma Mycoplasma Filter Specimen Control laidlawii pneumoniae AmiconUltra Cell + + 100 kDa Culture medium + + Washing solution + + Ultrafree Cell + 0.1 m Culture medium + + Washing solution + + Ultrafree Cell + + 0.22 m Culture medium + Washing solution + + +: trapping is possible, : trapping is impossible
[0185] 3. Checking of Proliferation of Mycoplasma
[0186] As for seven kinds of Mycoplasmas, it was checked how much the Mycoplasma was amplified when the Mycoplasma was added and cultured so as to have a concentration of 10 cfu/mL or less in the respective specimens of the cells, the culture medium, and the washing solution.
[0187] In a case where the specimen is a cryopreserved cell, 2 mL of a liquid culture medium for a Mycoplasma detection test, 100 L of a specimen, and 10 L of a Mycoplasma diluent prepared to contain a desired Mycoplasma were added to a well. The Mycoplasma was added such that 0.80 cfu of the Mycoplasma was contained in the case of testing Mycoplasma arginini, 0.54 cfu of the Mycoplasma was contained in the case of testing Mycoplasma salivarium, 0.68 cfu of the Mycoplasma was contained in the case of testing Mycoplasma pneumoniae, 0.60 cfu of the Mycoplasma was contained in the case of testing Mycoplasma fermentans, 0.60 cfu of the Mycoplasma was contained in the case of testing Mycoplasma orale, 0.74 cfu of the Mycoplasma was contained in the case of testing Mycoplasma hyorhinis, and 0.84 cfu the Mycoplasma was contained in the case of testing Acholeplasma laidlawii, per well. That is, the Mycoplasma was added such that the Mycoplasma would be 0.80 cfu/100 L (8.0 cfu/mL) in the case of testing Mycoplasma arginini, 0.54 cfu/100 L (5.4 cfu/mL) in the case of testing Mycoplasma salivarium, 0.68 cfu/100 L (6.8 cfu/mL) in the case of testing Mycoplasma pneumoniae, 0.60 cfu/100 L (6.0 cfu/mL) in the case of testing Mycoplasma fermentans, 0.60 cfu/100 L (6.0 cfu/mL) in the case of testing Mycoplasma orale, 0.74 cfu/100 L (7.4 cfu/mL) in the case of testing Mycoplasma hyorhinis, and 0.84 cfu/100 L (8.4 cfu/mL) in the case of testing Acholeplasma laidlawii, per 100 L of the specimen.
[0188] In a case where the specimen is a sheet preparation culture medium or a cell washing solution, 2 mL of a liquid culture medium for a Mycoplasma detection test, 500 L of a specimen, and 50 L of a Mycoplasma diluent prepared to contain a desired Mycoplasma were added to a well. The Mycoplasma was added such that 4.0 cfu of the Mycoplasma was contained in the case of testing Mycoplasma arginini, 2.7 cfu of the Mycoplasma was contained in the case of testing Mycoplasma salivarium, 3.4 cfu of the Mycoplasma was contained in the case of testing Mycoplasma pneumoniae, 3.0 cfu of the Mycoplasma was contained in the case of testing Mycoplasma fermentans, 3.0 cfu of the Mycoplasma was contained in the case of testing Mycoplasma orale, 3.7 cfu of the Mycoplasma was contained in the case of testing Mycoplasma hyorhinis, and 4.2 cfu the Mycoplasma was contained in the case of testing Acholeplasma laidlawii, per well. That is, the Mycoplasma was added such that the Mycoplasma would be 4.0 cfu/500 L (8.0 cfu/mL) in the case of testing Mycoplasma arginini, 2.7 cfu/500 L (5.4 cfu/mL) in the case of testing Mycoplasma salivarium, 3.4 cfu/500 L (6.8 cfu/mL) in the case of testing Mycoplasma pneumoniae, 3.0 cfu/500 L (6.0 cfu/mL) in the case of testing Mycoplasma fermentans, 3.0 cfu/500 L (6.0 cfu/mL) in the case of testing Mycoplasma orale, 3.7 cfu/500 L (7.4 cfu/mL) in the case of testing Mycoplasma hyorhinis, and 4.2 cfu/500 L (8.4 cfu/mL) in the case of testing Acholeplasma laidlawii, per 500 L of the specimen.
[0189] Six kinds of Mycoplasmas excluding Mycoplasma salivarium were subjected to aerobic cultivation under the conditions of 36 C. and 5% CO.sub.2, and Mycoplasma salivarium was subjected to anaerobic cultivation under the condition of 36 C. After 3 days from the cultivation, the culture solution was extracted from each well after 7 days, and the number of bacteria was measured.
[0190] The results are shown in
[0191] 4. Calculation of Detection Limit
[0192] In respective specimens of the cells, the culture medium, and the washing solution, detection limits of seven kinds of Mycoplasmas were calculated.
[0193] In a case where the specimen is a cryopreserved cell, 852 L of a liquid culture medium for a Mycoplasma detection test and 48 L of a specimen were added to a microtube, and 100 L of a Mycoplasma diluent prepared to contain a desired Mycoplasma was added thereto. The Mycoplasma was added so as to be 1000 cfu, 500 cfu, 100 cfu, and 50 cfu per microtube. That is, with respect to the total volume in the microtube, the Mycoplasma was added so as to have concentrations of 1000 cfu/mL, 500 cfu/mL, 100 cfu/m L, and 50 cfu/mL.
[0194] In a case where the specimen is a sheet preparation culture medium or a cell washing solution, 525 L of a liquid culture medium for a Mycoplasma detection test, 150 L of a specimen, and 75 L of a Mycoplasma diluent prepared to contain a desired Mycoplasma were added to a microtube. The Mycoplasma was added so as to be 750 cfu, 375 cfu, 75 cfu, and 37.5 cfu per microtube. That is, with respect to the total volume in the microtube, the Mycoplasma was added so as to have concentrations of 1000 cfu/m L, 500 cfu/m L, 100 cfu/m L, and 50 cfu/mL.
[0195] In a case where the specimen is a cryopreserved cell, 500 L of the supernatant subjected to centrifugation for 5 minutes at 4 C. and 400g was transferred to a centrifugal ultrafiltration filter (Merck Millipore) having a molecular weight cutoff of 100 kDa and then subjected to centrifugation for 10 minutes at 4 C. and 14,000g.
[0196] In a case where the specimen is a culture medium or a washing solution, 500 L was transferred to a centrifugal ultrafiltration filter (Merck Millipore) having a molecular weight cutoff of 100 kDa and then subjected to centrifugation for 10 minutes at 4 C. and 14,000g. 500 L of PBS was added thereto and subjected to centrifugation for 10 minutes at 4 C. and 14,000g, 500 L of PBS was then further added and subjected to vigorously pipetting, and the Mycoplasma trapped with the filter was recovered.
[0197] DNA was extracted from the total amount of the recovered liquid after removing impurities by using MagNA Pure LC DNA Isolation Kit-Large Volume (Roche) to finally obtain a 200 L DNA extract.
[0198] 10 L of the DNA extract was added to 90 L of PCR reaction solution (Takara Ex taq), and PCR was performed for one cycle of 5 minutes at 40 C., one cycle of 10 minutes at 94 C., 20 cycles of 30 seconds at 94 C., 30 seconds at 70 C., and 45 seconds at 72 C. (the part at 70 C. decreases by 1 C. per two cycles, up to 61 C.), 25 cycles of 30 seconds at 94 C., 30 seconds at 60 C., and 45 seconds at 72 C., and one cycle of 4 minutes at 72 C. As for the primer, the following sequences were used.
[0199] Primer sequences:
TABLE-US-00005 Forward: (SEQIDNO:1) 5-GGCGAATGGGTGAGTAACACG-3 Reverse: (SEQIDNO:2) 5-CGGATAACGCTTGCGACCTATG-3
[0200] The reaction solution after PCR was subjected to electrophoresis with an agarose gel, and then the presence or absence of a DNA band was checked.
[0201] Calculation was performed 24 times for respective Mycoplasma concentrations of 1000 cfu/m L, 500 cfu/m L, 100 cfu/m L, and 50 cfu/m L, and from the ratio of the Mycoplasma concentration and the number of positive cells (the number of cells in which a DNA band specific to the Mycoplasma was confirmed), probit analysis was performed using NATIONAL INSTITUTE OF INFECTIOUS DISEASE statistical analysis support software Bioassay Assist, and 95% detection sensitivity was calculated. The results are shown in Table 2. The detection limit of each Mycoplasma was 92 to 5647 cfu/m L.
[Table 2]
[0202]
TABLE-US-00006 TABLE 2 Detection limit Specimen M. arginini M. salivarium M. pneumoniae M. fermentans Cell 132 cfu/ml 202 cfu/mL 1043 cfu/mL 176 cfu/mL Culture 335 cfu/mL 474 cfu/mL 542 cfu/mL 124 cfu/mL medium Washing 473 cfu/mL 104 cfu/mL 502 cfu/mL 92 cfu/mL solution Specimen M. orale M. hyorhinis A. laidlawii Cell 1365 cfu/mL 1068 cfu/mL 3044 cfu/mL Culture 751 cfu/mL 1091 cfu/mL 2579 cfu/mL medium Washing 633 cfu/mL 544 cfu/mL 5647 cfu/mL solution
[0203] 5. Detectability of Mycoplasma
[0204] In the respective specimens of the cells, the culture medium, and the washing solution, the amount of the Mycoplasma amplified in the precultivation was compared with the detection sensitivity in this method, and it was verified whether the Mycoplasma contamination can be detected with a high sensitivity as the final test method. The amount of the Mycoplasma amplified in the precultivation and the detection sensitivity in this method are shown in Table 3 and
[Table 3]
[0205]
TABLE-US-00007 TABLE 3 Detectability of mycoplasma Detecting Mycoplasma Culture possibility contamination solution (possible: per 1 mL of after Detection A > B) specimen precultivation sensitivity (impossible: Specimen Mycoplasma (cfu/mL) (A) (cuf/mL) (B) (cfu/mL) A < B) Cell M. arginini 8.0 5.79 10.sup.9 132 Possible M. salivarium 5.4 3.53 10.sup.8 202 Possible M. pneumoniae 6.8 1.54 10.sup.3 1043 Possible M. fermentans 6.0 5.43 10.sup.5 176 Possible M. orale 6.0 1.17 10.sup.9 1365 Possible M. hyorhinis 7.4 1.58 10.sup.8 1068 Possible A. laidlawii 8.4 3.62 10.sup.7 3044 Possible Culture M. arginini 8.0 1.00 10.sup.9 335 Possible medium M. salivarium 5.4 6.18 10.sup.7 474 Possible M. pneumoniae 6.8 6.77 10.sup.3 542 Possible M. fermentans 6.0 1.24 10.sup.8 124 Possible M. orale 6.0 2.56 10.sup.7 751 Possible M. hyorhinis 7.4 6.20 10.sup.7 1091 Possible A. laidlawii 8.4 4.98 10.sup.7 2579 Possible Washing M. arginini 8.0 4.82 10.sup.8 473 Possible solution M. salivarium 5.4 6.22 10.sup.7 104 Possible M. pneumoniae 6.8 4.85 10.sup.3 502 Possible M. fermentans 6.0 3.38 10.sup.8 92 Possible M. orale 6.0 2.71 10.sup.8 633 Possible M. hyorhinis 7.4 1.84 10.sup.7 544 Possible A. laidlawii 8.4 1.44 10.sup.8 5647 Possible
[0206] 6. Mycoplasma Detection Test
[0207] 6.1. Precultivation
[0208] 500 L of a washing solution was added as a specimen to 2 mL of a liquid culture medium for a Mycoplasma detection test and then subjected to aerobic cultivation for 7 days under the conditions of 36 C. and 5% CO.sub.2. Similarly, 500 L of a washing solution was added as a specimen to 2 mL of a liquid culture medium for a Mycoplasma detection test and then subjected to anaerobic cultivation for 7 days under the condition of 36 C. As for a negative control, PBS was added instead of a specimen and the same operation was performed. Further, as a positive control, one obtained by adding 50 L of a Mycoplasma diluent containing 1500 cfu/L of Mycoplasma orale was subjected to aerobic cultivation, and one obtained by adding 50 L of a Mycoplasma diluent containing 1500 cfu/L of Mycoplasma salivarium was subjected to anaerobic cultivation.
[0209] 6.2. Impurity Removal
[0210] 500 L of a culture solution was transferred to a centrifugal ultrafiltration filter (Merck Millipore) having a molecular weight cutoff of 100 kDa and then subjected to centrifugation for 10 minutes at 4 C. and 14,000g. 500 L of PBS was added thereto and subjected to centrifugation for 10 minutes at 4 C. and 14,000g, 500 L of PBS was then further added and subjected to vigorously pipetting, and the Mycoplasma trapped with the filter was recovered.
[0211] 6.3. DNA Extraction
[0212] DNA was extracted from the total amount of the recovered liquid after removing impurities by using MagNA Pure LC DNA Isolation Kit-Large Volume (Roche) to finally obtain a 200 L DNA extract.
[0213] 6.4. PCR and Electrophoresis
[0214] 10 L of the DNA extract was added to 90 L of PCR reaction solution (Takara Ex taq), and PCR was performed for one cycle of 5 minutes at 40 C., one cycle of 10 minutes at 94 C., 20 cycles of 30 seconds at 94 C., 30 seconds at 70 C., and 45 seconds at 72 C. (the part at 70 C. decreases by 1 C. per two cycles, up to 61 C.), 25 cycles of 30 seconds at 94 C., 30 seconds at 60 C., and 45 seconds at 72 C., and one cycle of 4 minutes at 72 C. As for the primer, the following sequences were used.
[0215] Primer sequences:
TABLE-US-00008 Forward: (SEQIDNO:1) 5-GGCGAATGGGTGAGTAACACG-3 Reverse: (SEQIDNO:2) 5-CGGATAACGCTTGCGACCTATG-3
[0216] The reaction solution after PCR was subjected to electrophoresis with an agarose gel, and then the presence or absence of a DNA band was checked.
[0217] 6.5. Result
[0218] The result is shown in
[0219] The detailed description above describes versions of methods for testing for the presence or absence of a Mycoplasma in a specimen, methods of managing quality of a biotechnology-related product, and kits for use in these methods, representing examples of the inventive methods and kits. The invention is not limited, however, to the precise embodiments and variations described. Various changes, modifications and equivalents can be effected by one skilled in the art without departing from the spirit and scope of the invention as defined in the accompanying claims. It is expressly intended that all such changes, modifications and equivalents which fall within the scope of the claims are embraced by the claims.