Method for evaluation of function of phagocyte
10852302 ยท 2020-12-01
Assignee
Inventors
Cpc classification
G01N2333/70596
PHYSICS
C07K14/70596
CHEMISTRY; METALLURGY
C07K16/2896
CHEMISTRY; METALLURGY
International classification
G01N33/00
PHYSICS
G01N33/50
PHYSICS
C07K14/705
CHEMISTRY; METALLURGY
Abstract
A novel convenient method for evaluating the function of a phagocyte is provided. The method assays sCD14-ST, which is a humoral factor specifically produced in phagocytosis by the phagocyte and which is stable enough for use in an assay. Also provided is a method for detecting diseases associated with the phagocytosis by the phagocyte.
Claims
1. A method for detecting a disease associated with phagocytosis by a phagocyte comprising the steps of: obtaining a specimen from a subject, wherein said specimen is at least one body fluid selected from the group consisting of interstitial fluid, lymph, synovial fluid, milk, cerebrospinal fluid, pus, saliva, lacrimal fluid, mucus, nasal discharge, sputum, urine, ascites, amniotic fluid, seminal fluid and lavage fluids obtained after washing naval cavity, bronchus, lung, skin, peritoneal cavity and various organs; adding to the specimen a substance which increases phagocytic activity and which is engulfed by phagocytes in the specimen and which induces phagocytes in the specimen to produce an amount of sCD14-ST before measuring a total amount of sCD14-ST in the specimen; measuring the total amount of sCD14-ST, including the amount sCD14-ST which is produced by phagocytes after the phagocytosis of the substance; comparing the measured value with a standard value; determining whether the amount of the sCD14-ST in the specimen is higher than the standard value; and detecting a disease associated with phagocytosis by a phagocyte in the subject when the measured value is higher than the standard value, wherein the sCD14-ST is measured by a sandwich immunoassay system comprising: (a) an antibody binding to a peptide comprising 16 amino acids spanning from 53.sup.rd to 68.sup.th amino acids of human CD14 of SEQ ID NO: 1, and (b) an antibody binding to a peptide comprising an amino acid sequence at position 17 to 26 of SEQ ID NO: 1.
2. A method for detecting a rheumatoid arthritis, which comprises the steps of obtaining a specimen from a subject, wherein said specimen is a synovial fluid: adding to the specimen a substance which increases phagocytic activity and which is engulfed by phagocytes in the specimen before measuring the amount of sCD14-ST in the specimen; measuring the amount of sCD14-ST which is produced by phagocytes after the phagocytosis of the substance; comparing the measured value with a standard value; determining whether the amount of the sCD14-ST in the specimen is higher than the standard value; and detecting rheumatoid arthritis in the subject when a measured value is higher than the standard value, and wherein the sCD14-ST is measured by a sandwich immunoassay system comprising: (a) an antibody binding to a peptide comprising 16 amino acids spanning from 53rd to 68th amino acids of human CD14 of SEQ ID NO:1, and (b) an antibody binding to a peptide comprising an amino acid sequence at position 17 to 26 of SEQ ID NO: 1.
3. A method for detecting mastitis, which comprises the steps of: obtaining a specimen from a subject, wherein said specimen comprises milk: adding to the specimen a substance which increases phagocytic activity and which is engulfed by phagocytes in the specimen before measuring the amount of sCD14-ST in the specimen; measuring the amount of sCD14-ST which is produced by phagocytes after the phagocytosis of the substance; comparing the measured value with a standard value; determining whether the amount of the sCD14-ST in the specimen is higher than the standard value; and detecting mastitis in the subject when a measured value is higher than the standard value, and wherein the sCD14-ST is measured by a sandwich immunoassay system comprising: (a) an antibody binding to a peptide comprising 16 amino acids spanning from 53rd to 68th amino acids of human CD14 of SEQ ID NO:1, and (b) an antibody binding to a peptide comprising an amino acid sequence at position 17 to 26 of SEQ ID NO: 1.
4. The method according to claim 1, wherein said substance is zymosan.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
DESCRIPTION OF EMBODIMENTS
(10) 1. sCD14-ST (Soluble CD14 Antigen Subtype)
(11) The present invention is based on the finding that sCD14-ST is produced in the process of the engulfing and digestion of the foreign microorganism or foreign substance by the phagocyte. Of the sCD14, sCD14-ST has the characteristic that it is electrophoresed in SDS-PAGE to a molecular weight of 132 kDa under the non-reducing conditions, and it has retained the amino acid sequence of the CD14 on N terminal side. sCD14-ST also exhibits immunogenicity which is different from the high molecular weight sCD14. For example, while the human high molecular weight sCD14 is recognized by 3C10 antibody (ATCC TIB-228), human sCD14-ST does not bond to the 3C10 antibody.
(12) In the meanwhile, some antibodies specifically recognize the sCD14-ST while failing to recognize the high molecular weight sCD14. Such antibody is the peptide antibody whose epitope is the peptide at particular domain of the sCD14-ST, and the particular domain is the region between 3 and 4 in the secondary structure of the CD14 (Kim et al., Journal of Biological Chemistry, 280: 11347-11351, 2005). More specifically, the particular domain corresponds to 36th to 79th amino acid sequence in human CD14 (SEQ ID NO. 1), 38th to 81st amino acid sequence in rabbit CD14 (SEQ ID NO. 2), 36th to 79th amino acid sequence in mouse CD14 (SEQ ID NO. 3), and 36th to 77th amino acid sequence in bovine CD14 (SEQ ID NO. 4). The antibody is produced by using a peptide consisting consecutive 8 or more amino acids in the region for the antigen. The preferred are the peptide comprising 16 amino acids from 53rd to 68th of human CD14, and the peptide consisting 20 amino acids from 40th to 59th of rabbit CD14. While the region of 3 to 4 (including 3-2-3-4) of the high molecular weight sCD14 has sheet structure or helix structure, the region of 3 to 4 in the sCD14-ST can not retain its inherent tertiary structure since its sequence lacks substantial portion on its C terminal side compared to the high molecular weight sCD14. Such difference in the tertiary structure is believed to result in the difference of the recognizability by the antibody.
(13) Accordingly, the sCD14-ST can be characterized by the unique immunogenicity in addition to its electrophoresis to the molecular weight of 132 kDa under non-reducing conditions in SDS-PAGE and its retention of the N terminal region of the CD14. The unique immunogenicity means that it is recognized by the antibody produced by using an antigen comprising consecutive 8 or more amino acids in the 3 to 4 region of the CD14 for the antigen. sCD14-ST is also a factor which shows specific increase of the blood concentration in the case of sepsis or in the sepsis model animal induced by infection by living bacteria. For example, human sCD14-ST is electrophoresed in the SDS-PAGE to a molecular weight of 132 kDa under non-reducing conditions, and has on it N terminal side the sequence comprising 1st to 8th amino acid residues of the amino acid sequence defined in SEQ ID NO. 1, and it specifically binds to an antibody binding to the peptide consisting 16 amino acid residue at 53rd to 68th of the amino acid sequence defined in SEQ ID NO. 1. Furthermore, it may additionally have at least one characteristic feature selected from its specific binding to an antibody which binds to the peptide consisting 17th to 26th amino acid residues of the amino acid sequence defined in SEQ ID NO. 1; not binding to 3C10 antibody; not binding to MEM-18 antibody; not having LPS-binding ability; being obtainable from human serum; and being a factor which exhibits specific blood concentration increase in the sepsis patients.
(14) Since the sCD14-ST retains the amino acid sequence at the N terminal of the CD14, when the sCD14-ST is isolated and its N terminal amino acid sequence is analyzed, it includes the same amino acid sequence as the N terminal of the CD14. The requirement is that the amino acid sequence of at least 1st to 8th at the N terminal amino acid is the same as the CD14. For example, in the case of human, the sCD14-ST can be confirmed to have the sequence of 1st to 8th in the amino acid sequence of SEQ ID NO. 1, and in the case of rabbit, it would be confirmed to have the sequence of 1st to 8th in the amino acid sequence of SEQ ID NO. 2; in the case of mouse, it would be confirmed to have the sequence of 1st to 8th in the amino acid sequence of SEQ ID NO. 3; and in the case of bovine, it would be confirmed to have the sequence of 1st to 8th in the amino acid sequence of SEQ ID NO. 4.
(15) 2. Method for Evaluating the Function of a Phagocyte
(16) The phagocyte used in the present invention is not particularly limited as long as it has phagocytosis activity and it is from a mammal. The preferred, however, is a neutrophil. In view of the ease of preparation, leukocyte or granulocyte may be used as the specimen containing the neutrophil. Isolated cell line having the function of differentiating into granulocyte may also be used, and exemplary such cell lines include HL-60. Exemplary mammals include human, rabbit, mouse, rat, monkey, bovine, pig, sheep, goat, horse, dog, and cat.
(17) The phagocyte may be prepared from body fluids such as blood, interstitial fluid, lymph, synovial fluid, milk, cerebrospinal fluid, pus, saliva, lacrimal fluid, mucus, nasal discharge, sputum, urine, ascites, amniotic fluid, and seminal fluid. The phagocyte may also be prepared from lavage fluid of nasal cavity, bronchus, lung, skin, peritoneal cavity, various organs, joint, bone, and the like, or from a tissue such as skin, lung, kidney, and mucus.
(18) When the phagocyte is prepared from a living body, only phagocyte may be strictly isolated, or alternatively, a fraction containing phagocyte may be prepared. For example, leukocyte from blood, granulocyte from blood, and granulocyte from peritoneal lavage fluid may be used for the phagocyte used in the method of the present invention.
(19) The function of the phagocyte is the physiological function that is possessed by the phagocyte. In the present invention, the function of a phagocyte is evaluated by using the phagocytosis for the index of the phagocyte activity. The phagocyte may also have various functions such as the function of producing cytokines and the function of migration depending on the type of the phagocyte. However, the function common to all phagocytes is the phagocytosis. Accordingly, phagocytosis is preferably used for the index in determining whether the phagocyte has normal function as the phagocyte. In addition, since most types of phagocytes have immune function as an immune cell in the living body, evaluation of the phagocytosis of the phagocyte may mean evaluation of the immune function of the phagocyte.
(20) Accordingly, one preferred embodiment of the present invention is a method for assaying phagocytosis ability of the neutrophil, granulocyte, and/or leukocyte. Another preferred embodiment of the present invention is a method for evaluating immune function by assaying phagocytosis ability of the neutrophil, granulocyte, and/or leukocyte.
(21) The method for evaluating the function of a phagocyte of the present invention is characterized by its measurement of the sCD14-ST produced by the phagocyte. sCD14-ST is useful as a marker for evaluating the function of a phagocyte since it is produced during the phagocytosis by the phagocyte. The phagocytosis by the phagocyte starts upon contact of the phagocyte with a substance to be engulfed. The substance to be engulfed is a substance which induces the phagocytosis of the phagocyte, and the term phagocytosis used herein means the process which at least includes engulfing of the substance to be engulfed by the phagocyte and digestion in the cell of the engulfed substance. Examples of the substance to be engulfed which is engulfed and digested by the phagocyte include cells such as bacteria and fungi as well as zymosan. In the meanwhile, a substance such as microbeads or latex beads which will not be digested after the engulfing is not the substance to be engulfed of the present invention.
(22) The measurement of the sCD14-ST is conducted by using a solution containing a phagocyte or its supernatant. The term solution used herein means a culture medium, a cell fractionation solution, a cell assay solution, a physiological saline solution, a body fluid, and the like. When the phagocyte is prepared from a living body, and the phagocyte is already in the process of engulfing the endogenous substance to be engulfed, the function of the phagocyte can be evaluated by directly assaying the thus prepared phagocyte-containing solution or its supernatant.
(23) When the substance to be engulfed is brought in contact with the phagocyte, the substance to be engulfed may be added to the solution containing the phagocyte. Alternatively, the solution containing the phagocyte may be added to a container having the substance to be engulfed immobilized to its interior surface. The substance to be engulfed is preferably zymosan in view of the ease of handling.
(24) The system used for the measurement of the sCD14-ST is not particularly limited as long as the sCD14-ST is detected. The preferred, however, is the immunological assay using an antibody which specifically binds to the sCD14-ST. The immunological assay system is preferably selected from direct adsorption, sandwich method, aggregation, solid phase immobilization, and reaction in a solution. The most preferred is the use of sandwich method (sandwich immunoassay).
(25) Sandwich immunoassay is a method in which at least two types of antibodies each recognizing different site of the protein to be assayed are used to form an antibody-antigen-antibody complex. The sandwich immunoassay can be carried out by the methods known in the art, and the assay principle, applications, and improvements are described, for example, in Eiji Ishikawa Ultrahigh sensitivity enzyme immunoassay method, Gakkai Shuppan Center (1993); Nao Matsuhashi et al. ed. New uses of immunoassay and use of immunoassay for the development of diagnostic and therapeutic drugs, Keiei-Kyouiku Shuppan (1985); and Eiji Ishikawa et al. ed. Enzyme immunoassay (3rd ed.), Igaku-Shoin (1987).
(26) The antibody which specifically binds to the sCD14-ST is an antibody which binds to a peptide comprising the sequence of 8 or more consecutive amino acid residues in the region between 3 and 4 in the secondary structure of CD14. Examples of such antibodies include S68 antibody described in WO 2005/108429 and F1301-9-1 antibody described in Example 1 of the present invention. Use of another antibody is required when sandwich immunoassay is used, and this antibody does not have to be an antibody which specifically binds to the sCD14-ST, and such antibody may also be an antibody which recognizes both the high molecular weight sCD14 and the sCD14-ST. Examples of such antibodies include F1106-13-3 antibody and F1031-8-3 antibody described in WO 2005/108429 and F1258-7-2 antibody described in Example 2 of the present invention. These antibodies may be either a polyclonal antibody or a monoclonal antibody. In the case of the sandwich immunoassay, the antibodies used are preferably a monoclonal antibody. The antibody may also be a fragment of such monoclonal antibody. The term antibody fragment used herein means any one of the Fab, Fab, and F(ab)2 of such monoclonal antibody.
(27) In the immunological assay system, existence the sCD14-ST is confirmed by forming a complex of the sCD14-ST with an antibody, and detecting the complex by means of the label attached to the complex. Exemplary labels include an enzyme such as peroxidase, alkaline phosphatase, -D-galactosidase, oxidase, or uricase; a chemiluminescent substance such as acrydinium or its derivative, or aequorin or its analog; a fluorescent substance such as FITC or a lanthanoid such as europium (Eu) or samarium (Sm); and a colorant, gold colloid, colored latex, or an isotope. When a chemiluminescent substance, a fluorescent substance, or a colorant label, or an isotope is used for the label, the assay may be completed by optically detecting the label by an assay apparatus adequately selected for the label. When the assay is conducted by a kit based on immunochromatography or flow through method using a colorant, gold colloid, or colored latex for the label, the assay may be completed by visual inspection.
(28) The immunological assay system may be provided in the form of a kit. In such a case, the kit should include an antibody which specifically binds to the sCD14-ST as a critical component, and also components required for enabling the detection of the complex by means of the label after forming the complex of the sCD14-ST and the antibody. For example, the kit may include an insoluble carrier (plastic plate, latex particles, etc.) having the antibody immobilized thereon, a marker enzyme such as peroxidase, a marker substance such as gold colloid, a chromogenic substrate such as tetramethyl benzidine (TMB), a specific binding substance for improving detection sensitivity such as biotin-streptavidin, a blocking agent, a dilute solution, a washing solution, a reference substance, and the like.
(29) The sCD14-ST in the solution containing a phagocyte or its supernatant is qualitatively and/or quantitatively measured. The result of the measurement is compared with the standard value to determine the presence and/or amount of the sCD14-ST to thereby evaluate presence and/or degree of the phagocytosis by the phagocyte. The standard value may be adequately set depending on the object of the assay. For example, the result of the measurement for the solution not containing the phagocyte, the solution before contacting with the substance to be engulfed, or their supernatant may be used as the negative standard value. The phagocytosis by the phagocyte is evaluated by determining whether the measurement of the specimen is higher than the negative standard value. A calibration curve may also be depicted from the measurements of the sCD14-ST standard substance for use as the standard. In this case, the phagocytosis by the phagocyte is evaluated by comparing the measurement for the specimen with the calibration curve to determine the amount of the sCD14-ST in the specimen. The degree of the function of the phagocyte in the specimen or the degree of the activation of the phagocyte may be evaluated by using the standard value of the number of the phagocyte used in the assay and/or the amount of the sCD14-ST produced per unit time. The standard substance of the sCD14-ST may be the sCD14-ST purified from blood, sCD14-ST which has been produced by phagocytotic stimulus by the phagocyte followed by purification, recombinant sCD14-ST, or sCD14-ST produced by peptide synthesis. The method used for the purification of the sCD14-ST and the production method of the recombinant sCD14-ST are described in WO 2005/108429.
(30) 3. Various Detection and Evaluation Methods by Evaluating Function of the Phagocyte Collected from the Subject
(31) The following detection and evaluation is enabled if the function of the phagocyte collected from the subject is evaluated by using the method described in the section of 2. Method for evaluating the function of a phagocyte.
(32) A) Detection and evaluation of whether the subject is suffering from a disease associated with dysfunction of the phagocyte, the stage of the disease, and/or severity of the disease.
(33) B) Detection and evaluation of change such as decrease or enhancement, abnormality, and/or degree of the immune function of the subject.
(34) C) Detection and evaluation of effect of the drug by evaluating the function of the phagocyte collected from the subject during and/or after the drug administration.
(35) D) Provision of an index for the quality rating of the phagocyte when the phagocyte is used in regenerative medicine.
(36) In detecting and evaluating the disease associated with phagocyte dysfunction, the process should at least include the step of evaluating the function of the phagocyte from the subject by using the method described in the section of 2. Method for evaluating the function of a phagocyte, and the process may further comprise the steps of comparing the evaluation results with the normal value, and determining the suffering and/or the degree of the disease based on whether the function of the phagocyte collected from the subject is higher or lower than the normal value.
(37) The term normal value used herein means the value obtained by preliminarily measuring the function of the phagocyte collected from the subjects not suffering from the disease, namely, the healthy subjects, and standardizing the measurements by calculating the average of the measurements or selecting a certain range from the measurements. While comparison of the measurement of the specimen with the normal value may be conducted by simply comparing the values, (average2SD) or (average3SD) in the normal subjects may be used as cut off values, and the specimen with the measurement higher or lower than the cut off values may be determined to have phagocyte dysfunction. The measurement value may also be used for evaluating the stage of the disease and/or severity of the disease.
(38) Examples of the disease associated with the phagocyte dysfunction include uremia, decrease in the activity of serum opsonin, complement deficiency, congenital phagocytosis dysfunction, chronic granulomatous disease, myeloperoxidase defect, leukemia, malignant lymphoma, bacterial endocarditis, diabetes, and hepatic cirrhosis. For example, chronic granulomatous disease is a congenital phagocyte dysfunction caused by the defect in the active oxygen production by the neutrophil which results in repeated suffering from serious infection by bacteria and fungi. The neutrophil from the patient suffering from the chronic granulomatous disease has the function of phagocytosis (engulfing of the foreign substance) but not the digestive function. Accordingly, abnormality can not be detected by the evaluation of the engulfing of the latex beads while evaluation of the phagocytosis using the production of the sCD14-ST for the index can detect the phagocyte dysfunction.
(39) Evaluation of the immune function may be conducted according to the detection and evaluation of the disease associated with the phagocyte dysfunction. The function of a phagocyte, and in particular, the phagocytosis is an important defense mechanism at the earliest stage of the immune response, and phagocyte dysfunction leads to abnormal immune function. Accordingly, the evaluation of the immune function may be conducted by understanding the phagocyte dysfunction as the immune function.
(40) In detecting and evaluating the effects of the drug, the process should at least include the step of evaluating the function of the phagocyte for the phagocyte collected from the subject during and/or after the drug administration by using the method described in the section of 2. Method for evaluating the function of a phagocyte, and the process may further comprise the steps of comparing the evaluation results with the normal value and/or the results before the drug administration, and determining the presence and/or the degree of the change in the function of the phagocyte collected from the subject by the drug administration. As described above, the term normal value is the measurement obtained by assaying the function of the phagocyte from healthy subjects.
(41) If change in the function of a phagocyte during and/or after the drug administration could be detected after administering an immunosuppressant, an immunostimulant, an anticancer agent, or the like, effectiveness of the drug and the degree of the side effects can be confirmed, and this will serve a useful guideline for drug selection and determination of its dose. Degree of the change of the function of a phagocyte, namely, change in the amount of the sCD14-ST produced can be used for the index of the degree of the drug effectiveness. For example, phagocytosis of the neutrophil in the peripheral blood may be compared before and after the G-CSF administration to evaluate how the neutrophil having normal function had increased by the G-CSF administration.
(42) When the phagocyte is evaluated for use of the phagocyte in regenerative medicine, the phagocyte used may be measured for its phagocytosis by using the production of the sCD14-ST for the index to thereby determine whether the phagocyte has the normal function as a phagocyte and/or the phagocyte activity. The term regenerative medicine used herein includes autologous cell transplantation in which leukocyte or the like collected from the patient is cultivated and treated outside the body of the patient and transplanted back into the patient as well as cross-cell transplantation in which the leukocyte or the like collected from a normal donor is transplanted to a patient. After the preparation of the phagocyte for transplantation, the method described in the section of 2. Method for evaluating the function of a phagocyte may be used for testing whether the phagocyte has a certain quality. The function of the prepared phagocyte is compared with the standard value, and if the measured value exceeds the standard value, the phagocyte is determined to have a quality sufficient in the regenerative medicine. While the standard value may be adequately set depending on the object of the regenerative medicine, the evaluation may be conducted generally by comparison with the phagocytosis of the normal phagocyte. When the value measured is lower than the standard value, the phagocyte should be determined to have a quality inadequate for the transplantation due to the loss of the function or cell activity of the phagocyte in the process of its preparation.
(43) 4. Screening for a Substance which Regulates the Phagocytic Function
(44) Screening for a substance which regulates the phagocytic function may also be conducted by using the method described in the section of 2. Method for evaluating the function of a phagocyte. More specifically, the present invention provides a method for screening a substance which regulates the phagocytic function comprising the steps of:
(45) 1) contacting a phagocyte with an analyte,
(46) 2) measuring the sCD14-ST produced by the phagocyte, and
(47) 3) evaluating effects of the analyte on the phagocytosis by the phagocyte.
(48) The step of 1) contacting a phagocyte with an analyte may be carried out so that the phagocyte and the analyte are contacted in the presence of the substance to be engulfed.
(49) The a substance which regulates the phagocytic function is a substance which promotes or suppresses the phagocytosis of the phagocyte. For example, when a known a substance which regulates the phagocytic function such as Wortomanin or Cytochalasin D is used for the analyte, and this analyte is brought in contact with the phagocyte to measure the sCD14-ST produced by the phagocyte, amount of the sCD14-ST produced decreases with the addition of the analyte, and the phagocytosis-suppressing effect is thereby confirmed. Similarly, a substance whose phagocytic function-regulating activity is to be evaluated may be used for the analyte, and this analyte may be contacted with the phagocyte to measure the amount of the sCD14-ST produced, and this amount of the sCD14-ST may be used as an index for the effect of the sCD14-ST on the phagocytosis.
(50) 5. Method for Detecting Disease Associated with Phagocytosis
(51) The present invention also provides a method for detecting a disease associated with phagocytosis by the phagocyte. In this method, the sCD14-ST in the specimen collected from the subject is measured, and the result is compared with the normal value to determine whether the amount of the sCD14-ST in the specimen is higher than the normal value to thereby detect whether the subject is suffering from a disease associated with phagocytosis by the phagocyte, stage of the disease, and/or severity of the disease.
(52) The test subject is not particularly limited as long as it is a mammal. Exemplary subjects include mammals such as human, monkey, rat, mouse, rabbit, bovine, pig, sheep, goat, horse, dog, and cat.
(53) The disease associated with phagocytosis by the phagocyte is a disease in which phagocytosis by the phagocyte occurs in the lesion, and in particular, a disease associated with local phagocytosis by autoimmune response or infection. Exemplary such diseases include local diseases such as autoimmune diseases, rheumatoid arthritis, mastitis, gout, glomerulonephritis, ulcerous colitis, Mediterranean fever, otitis media, rhinitis, pneumonia, tuberculosis, cystitis, amniotic fluid infection, and pyosemia. However, diseases associated with systemic infection and sepsis are not included the present invention.
(54) Exemplary specimen include body fluids such as interstitial fluid, lymph, synovial fluid, milk, cerebrospinal fluid, pus, saliva, lacrimal fluid, mucus, nasal discharge, sputum, urine, ascites, amniotic fluid, and seminal fluid as well as lavage fluid obtained after washing nasal cavity, bronchus, lung, skin, peritoneal cavity, various organs, joint, bone, and the like. However, blood is not to be used in the present invention.
(55) The measurement of the sCD14-ST may be conducted according to the method described in the section of 2. Method for evaluating the function of a phagocyte.
(56) The normal value used may be the value obtained by preliminarily measuring the subjects not suffering from the disease, namely, the healthy subjects, and standardizing the measurements by calculating the average of the measurements or selecting a certain range from the measurements. When the value measured for the specimen collected from a healthy subject is substantially equivalent with the background of the assay system, a value standardized by calculating the average of the background value or selecting a range may be used as the normal value. The background value of the assay system is the value measured for the assay system having not the specimen but the buffer and the assay solution added thereto. While comparison of the measurement of the specimen with the normal value may be conducted by simply comparing the values, (average+2SD) or (average+3SD) of the normal subjects may be used as cut off values, and the specimen with the measurement higher than the cut off value may be determined as positive. The measurement value may also be used for the determination of the stage of the disease and/or severity of the disease, and more specifically, a higher measurement value may mean higher stage and higher severity of the disease.
(57) The specimen may or may not contain the phagocyte. The sCD14-ST in the specimen can be directly measured to evaluate the phagocytosis in the living body, namely, to determine the suffering from and/or severity of the disease, partly because the sCD14-ST produced as the results of the phagocytosis by the phagocyte in the living body is present in the specimen. For example, in the case of arthritis model animal, the sCD14-ST in synovial fluid or joint lavage fluid can be measured to diagnose the disease associated with inflammation at the joint, and in particular, rheumatoid arthritis, osteoarthritis, periarthritis scapulohumeralis, and the like, partly because increase in the concentration of the sCD14-ST in the synovial fluid or joint lavage fluid is detectable.
(58) On the other hand, presence and/or amount of the phagocyte in the body fluid or tissue lavage fluid may be detected to thereby determine the suffering from and/or severity of the disease. In this case, a substance to be engulfed may be added to the specimen to measure the sCD14-ST produced. For example, a substance to be engulfed may be added to milk, and the sCD14-ST produced may be measured for diagnosing mastitis. This is particularly useful for detecting bovine mastitis.
(59) The present invention has been described by referring preferred embodiments which by no means limit the scope of the invention. Various changes and modification may occur to those skilled in the art, and such changes and modification can be made without deviating the scope of the present invention.
EXAMPLES
Example 1
Production of F1301-9-1 Antibody by Using a Synthetic Peptide for the Antigen
(60) 1-(1) Preparation of the Peptide Used for the Antigen
(61) A peptide having the sequence defined in SEQ ID NO. 5 (corresponding to the sequence of 40th to 59th amino acid residues of rabbit CD14 amino acid sequence) having cysteine inserted at its N terminal for ligation at its end with the carrier protein via SH group was synthesized using peptide synthesizer ABI433A (Applied Biosystems). The peptide was purified by the method commonly used in the art to obtain 2 to 3 mg of the peptide.
(62) 1-(2) Preparation of Peptide Carrier Protein Using the Synthetic Peptide
(63) The peptide prepared in 1-(1) was dissolved in distilled water to 10 mg/mL, and equal amount of this solution and 10 mg/mL Imject Maleimide Activated Keyhole Limpet Hemocyanin (KLH) (PIERCE) were mixed. The mixture was allowed to react at room temperature for 2 hours for the binding of the peptide with the carrier protein (this product is hereinafter referred to as SEQ ID NO. 5 peptideKLH). In the meanwhile, the peptide prepared in 1-(1) was dissolved in distilled water to 10 mg/mL, equal amount of this solution and 10 mg/mL Imject Maleimide Activated Bovine Serum Albumin (BSA) (PIERCE) were mixed. The mixture was allowed to react at room temperature for 2 hours for the binding of the peptide with the carrier protein (this product is hereinafter referred to as SEQ ID NO. 5 peptideBSA).
(64) 1-(3) Production of Hybridoma Clone by Using the Synthetic Peptide for the Antigen
(65) In order to prepare a monoclonal antibody for the peptide prepared in 1(1), rat was immunized with SEQ ID NO. 5 peptideKLH. More specifically, 100 g of SEQ ID NO. 5 peptideKLH was diluted with 100 L physiological saline, and equal amount of this solution and 100 L Freund's complete adjuvant (DIFCO) were mixed. 100 L of this mixture was administered to foot pad of a female 8 week-old Wistar rat (Japan SLC, Inc.). After 11 days, 100 g of SEQ ID NO. 5 peptideKLH which had been diluted with 200 L physiological saline was again administered to the foot pad. 3 days after the administration, lymphocytes were separated from ilium lymph node, and the thus obtained lymphocytes were mixed with Sp2/OAg14 (ATCC CRL-1581), and cell fusion was conducted according to the procedure described in Introduction to experimental methods of monoclonal antibody edited by Tamie Ando and Takeshi Chiba (Kodan-sha) by using polyethylene glycol. Hybridoma was selected by HAT medium, and after 1 week, the hybridoma producing the desired antibody was selected by ELISA. More specifically, SEQ ID NO. 5 peptideBSA was diluted with 0.076M phosphate buffer (pH 7.4) (hereinafter referred to as D-PBS) to 10 g/mL, and added to an immunoplate (Maxisorb, Nunc) at 50 L/well. After allowing the reaction to proceed overnight at 4 C., the well was washed 5 times with ion exchanged water. The well was blocked by adding 100 L of D-PBS (pH 7.4) containing 2% Stabilgurd to each well. Next, the supernatant of the hybridoma culture was added to each well, and after reacting at 37 C. for 1 hour, the well was washed 3 times by physiological saline containing 0.05% Tween 20. Peroxidase-labeled anti-rat immunoglobulin antibody (DAKO) was diluted 1000 times with D-PBS (pH 7.4) containing 10% rabbit serum, and 50 L was added to each well. After reacting at 37 C. for 1 hour, the well was washed 3 times by the same procedure. TMB solution (BioFX) was added to each well, and after reacting at room temperature for 10 minutes, the reaction was ceased by adding 0.5M sulfuric acid solution. Absorbance at 450 nm was measured by plate spectrophotometer (NJ-2100, Intermed Japan), and the cells in the well with the increased absorbance were collected and cloned by limiting dilution analysis. After 11 days, screening was conducted by the same method, and clone F1301-9-1 producing the antibody which reacts with the peptide of SEQ ID NO. 5 was obtained.
(66) 1-(4) Purification of Antibody from the Supernatant of the Hybridoma
(67) The F1301-9-1 obtained in 1-(3) was cultivated at 3 L scale in SFM medium (GIBCO). The supernatant of this medium was filtered through 0.45 m filter to remove the cells, and the filtrate was applied to a Protein G column. Next, the adsorbed fraction was eluted with an acid, and the eluate was immediately neutralized by adding 1/10 volume of 1M Tris-HCl (pH 8.0). The eluate was subjected to buffer exchange with physiological saline by using an ultrafilter membrane to obtain the purified antibody.
Example 2
Preparation of F1258-7-2 Antibody by Using the Synthetic Peptide for the Antigen
(68) 2-(1) Preparation of the Peptide Used for the Antigen
(69) A peptide having the sequence defined in SEQ ID NO. 6 (corresponding to the sequence of 1st to 30th amino acids of rabbit CD14 amino acid sequence) having cysteine inserted at its N terminal for ligation at its end with the carrier protein via SH group was synthesized using peptide synthesizer ABI433A (Applied Biosystems). The peptide was purified by the method commonly used in the art to obtain 2 to 3 mg of the peptide.
(70) 2-(2) Preparation of Peptide Carrier Protein Using the Synthetic Peptide
(71) SEQ ID NO. 6 peptideKLH and SEQ ID NO. 6 peptideBSA were prepared by the method similar to that of to 1-(2).
(72) 2-(3) Production of Hybridoma Clone by Using the Synthetic Peptide for the Antigen
(73) Clone F1258-7-2 producing the monoclonal antibody for the SEQ ID NO. 6 peptide prepared in 2-(2) was produced by the method similar to that of to 1-(3).
(74) 2-(4) Purification of Antibody from the Supernatant of the Hybridoma
(75) A monoclonal antibody was purified from the supernatant of the culture of the hybridoma clone of the SEQ ID NO. 6 peptide prepared in 2-(3) by the method similar to that of to 1-(4).
Example 3
Preparation of the Assay System for Rabbit sCD14-ST
(76) In order to prepare a system capable of specifically detecting of the rabbit sCD14-ST, a sandwich ELISA system was prepared by using the antibodies prepared in Example 1-(4) and Example 2-(4).
(77) 3-(1) Preparation of F1258-7-2 Fab-HRP
(78) To prepare F(ab)2 of the F1258-7-2 antibody, the purified F1258-7-2 antibody prepared in Example 2-(4) was treated with pepsin. More specifically, the purified F1258-7-2 antibody was subjected to buffer exchange with 100 mM acetate buffer (pH 4.4) containing 2M urea, and pepsin (Boehringer) was added so that antibody: enzyme was 30:1 (weight ratio). After the addition, the reaction was promoted at 37 C. for 6 hours. At the completion of the reaction, 1M Tris-hydrochloric acid buffer (pH 8.0) was added to bring the pH back to approximately neutral. Next, F(ab)2 was purified. More specifically, the antibody treated with pepsin was applied to Prosep G (Millipore) to remove the Fc moiety and the pepsin, and the adsorbed fraction was eluted with an acid. The adsorbed fraction was further applied to Superdex 200 (Amersham) to remove the uncleaved antibody to thereby obtain the F(ab)2 of the F1258-7-2. The purified F(ab)2 was confirmed for its purity by SDS-PAGE, and protein was quantitated by using Protein Assay Dye Reagent (Bio-Rad) using bovine serum IgG for the standard. The thus obtained F1258-7-2 F(ab)2 antibody was partially reduced by Peroxidase Labeling Kit SH (Dojindo Laboratories), and cysteine residue at the hinge was labeled with peroxidase to produce F1258-7-2 Fab-HRP.
(79) 3-(2) Preparation of Rabbit sCD14-ST Sandwich ELISA System
(80) Two step sandwich ELISA system was constructed by using the F1301-9-1 antibody produced in Example 1-(4) for the solid phase antibody, and the F1258-7-2 Fab-HRP antibody prepared in Example 3-(1) for the labeling antibody. More specifically, the F1301-9-1 antibody was diluted with D-PBS (pH 7.4) to 10 g/mL, and added to the wells of immunoplate (Maxisorb, Nunc) at 50 L/well. After allowing the reaction to proceed overnight at 4 C., the well was washed 5 times with ion exchanged water. D-PBS (pH 7.4) containing 5% StabilGuard (SurModics) and 0.1% Tween 20 was added to the wells at 200 L/well for blocking. Next, the specimen was diluted by using 150 mM phosphate buffer (pH 6.0) containing 5% normal rabbit serum (serum from which soluble CD14 antigen has been removed by using the rabbit CD14 affinity antibody column), 1% BSA, and 0.1% Tween 20 for dilution, and the diluted specimen was added to the well at 50 L/well and allowed to react at 25 C. for 3 hours. After completion of the reaction, the well was washed 5 times with physiological saline containing 0.05% Tween 20. The F1258-7-2 Fab-HRP was diluted with 75 mM phosphate buffer (pH 6.4) containing 4% rat serum and 0.05% Tween 20, and added to the well at 50 L/well. After allowing to react at 25 C. for 2 hours, the well was washed 5 times in the similar manner. Tetramethylbenzidine solution (TMB, BioFX) was added to the well, and the reaction was allowed to proceed at room temperature for 15 minutes. The reaction was ceased with 0.5M sulfuric acid solution, and absorbance at 450 nm was measured by using a plate spectrophotometer (NJ-2100, Intermed Japan).
(81) The standard substance used was recombinant rabbit sCD14-ST. The recombinant rabbit sCD14-ST was prepared according to the method described in WO 2005/108429. More specifically, a plasmid having thrombin cleavage site inserted after 66th amino acid residue of the amino acid sequence of the rabbit CD14 was produced, and this plasmid was transiently expressed in the supernatant of COS cell culture. After purifying the sCD14 in the culture supernatant, the sCD14 was cleaved with thrombin and subjected to gel filtration chromatography to purify the recombinant rabbit sCD14-ST.
(82) The thus prepared sandwich ELISA could detect the recombinant sCD14-ST in a dose-dependent manner as shown in
Example 4
Examination of the sCD14-ST Production in Rabbit Subject Model
(83) 4-(1) Production of LPS-Induced Rabbit Sepsis Model
(84) LPS-induced rabbit sepsis model was prepared by administering LPS (Salmoella Minnesota Re595, Sigma) to auricular vein of a New Zealand white rabbit (1.8 to 2.6 kg, Kitayama Labes Co., Ltd.) at a dose of 10 g/kg. Blood was collected from the auricular artery before and 1.5 hours after the LPS administration. Citric acid was added to the blood.
(85) 4-(2) Production of Rabbit Live Bacteria-Infected Model (CLP Model)
(86) Rabbit CLP (cecal ligation and puncture) model was prepared by surgery of a New Zealand white rabbit (1.8 to 2.6 kg, Kitayama Labes Co., Ltd.). More specifically, the animal which had been fasted overnight underwent general anesthesia by administering 0.35 mg/kg of Domitor (medetomidine hydrochloride, Meiji Seika Kaisha, Ltd.) and 5 mg/kg of Ketalar for Animal (ketamine, Sankyo) to its auricular vein. After dissecting abdomen and taking cecum out of the peritoneal cavity, the cecum was ligated at the downstream of the ileocecum and 2 incisions each having a width of about 2 cm were made with ophthalmic scissors. The cecum was squeezed with forceps to confirm that the cecum content came out of the incision, and then, the cecum was placed back in the peritoneal cavity, and the peritoneum and the skin were closed with surgical suture. After closing the abdomen, 50 mL/kg of physiological saline was subcutaneously administered, and 0.35 mg/kg of Antisedan (atipamezole hydrochloride, Meiji Seika Kaisha, Ltd.) was administered to auricular vein to complete the surgery. Blood was collected from the auricular artery before and 2 hours after the surgery for the CLP model production. Citric acid was added to the blood.
(87) 4-(3) Measurement of the Blood sCD14-ST in the Rabbit Sepsis Model
(88) Plasma was prepared from the blood collected in Examples 4-(1) and 4-(2) by centrifugation, and sCD14-ST was measured according to the method described in Example 3-(2). The results are shown in
Example 5
Phagocytosis Experiment Using Granulocyte from Rabbit Peritoneal Cavity
(89) 5-(1) Collection of Granulocyte from Rabbit Peritoneal Cavity
(90) Glycogen was dissolved with physiological saline to 0.1%, and 150 mL of this solution was administered to peritoneal cavity of New Zealand white male rabbit (Kitayama Labes Co., Ltd., 1.64 to 1.92 kg). 16 hours after the administration, the rabbit was euthanized by excessive anesthesia, and the peritoneal cavity was washed with physiological saline to collect the granulocyte.
(91) 5-(2) Production of sCD14-ST by Various Stimulants
(92) Various leukocyte stimulants were added to the granulocyte to evaluate the amount of sCD14-ST produced. More specifically, granulocyte from the rabbit peritoneal cavity collected in Example 5-(1) was suspended in HBSS buffer (GIBCO 14025) containing 2% normal rabbit serum, 2 mM Glutamin, and 10 mM HEPES (hereinafter referred to as cell assay buffer) to a cell concentration of 1107 cells/mL, and added to the wells of 96 well culture plate (Nunclon Surface, Nunc) at 100 L/well. Next, various stimulants were adjusted to 3 times the target concentration with the cell assay buffer, and added to the well at 50 L/well. After incubating at 37 C. for 2 hours, the supernatant was collected by centrifugation and sCD14-ST was measured by the assay system of Example 3-(2). The results are shown in
(93) 5-(3) Action of Various Inhibitors on sCD14-ST Production
(94) Example 5-(2) indicated that phagocytosis by the granulocyte is related to the production of the rabbit sCD14-ST. Accordingly, relation between the production of the sCD14-ST and the phagocytosis was examined by using various phagocytosis inhibitors. More specifically, the granulocyte from rabbit peritoneal cavity collected in Example 5-(1) was suspended in the cell assay buffer to a cell concentration of 1107 cells/mL, and the suspension was added to the wells of 48 well culture plate (48 well Cell Culture Cluster, Corning) at 200 L/well. Next, various inhibitors were adjusted to 3 times the target concentration with the cell assay buffer, and added to the well at 100 L/well. After incubating at 37 C. for 30 minutes, 20 times by cell count of E. coli was added to the granulocyte (E. coli was added by counting 1 colony forming unit as 1 cell). After incubating at 37 C. for 2 hours, the supernatant was collected by centrifugation, and the sCD14-ST was assayed by using the assay system of Example 3-(2). The results are shown in
Example 6
Measurement of sCD14-ST in Synovial Fluid in Rabbit Arthritis Model
(95) 6-(1) Preparation of Methylated BSA
(96) 1 g of BSA (SIGMA) was dissolved in 100 mL of D-PBS (pH 7.4) containing 4% paraformaldehyde, and after adjusting the pH to 8.5 by using an alkali, the reaction was allowed to proceed at room temperature for 1 hour. Next, 80 mg of sodium borohydride was added, and after allowing the reduction reaction to proceed at 4 C. for 2 hours, the buffer was exchanged with D-PBS (pH 7.4) by using a ultrafilter.
(97) 6-(2) Confirmation of Immune Reaction by ELISA
(98) Immune reaction for the antigen was confirmed by ELISA. More specifically, methylated BSA was diluted with D-PBS (pH 7.4) to 10 g/mL, and added to immunoplate (Maxisorp, Nunc) at 50 L/well. After allowing the reaction to proceed at 37 C. for 1 hour and washing 5 times with ion exchanged water, the well was blocked by adding 100 L/well of D-PBS (pH 7.4) containing 5% StabilGuard (SurModics). Next, the blood samples (serum) of the rabbits used in the evaluation of Example 6-(3) were diluted with D-PBS (pH 7.4) containing 1% StabilGuard (SurModics), and added to the well at 100 L/well. After the reaction at room temperature for 1 hour, the well was washed 5 times with physiological saline containing 0.05% Tween 20. Next, peroxidase-labeled anti-rabbit immunoglobulin antibody (DAKO, P448) was diluted 1000 times with D-PBS containing 5% goat serum, and added to the well at 50 L/well. After allowing to react at room temperature for 1 hour, the well was washed 5 times in the similar manner. TMB solution (BioFX) was added to the well, and the reaction was allowed to proceed at room temperature for 10 minutes. The reaction was ceased with 0.5M sulfuric acid solution, and absorbance at 450 nm was measured by using a plate spectrophotometer (Multiscan JX, Dainippon Pharmaceutical Co., Ltd.).
(99) 6-(3) Measurement of sCD14-ST in Rabbit Arthritis Model
(100) 500 L (5 mg) of the methylated BSA prepared in Example 6-(1) and 500 L of complete Freund's adjuvant (DIFCO) were mixed, and this mixture was administered subcutaneously at the back, at the sole of the hind leg, and intramuscularly at the thigh of New Zealand white male rabbits (10 to 11 week old, Kitayama Labes Co., Ltd.) (hereinafter referred to as the antigen-sensitized group). Simultaneously, the solvent having no methylated BSA added thereto was administered to the same number of rabbits (hereinafter referred to as the solvent control group). After 2 weeks, 500 L (5 mg) of methylated BSA and 500 L of incomplete Freund's adjuvant (DIFCO) were mixed, and this mixture was used to again sensitize the antigen-sensitized group. For the solvent control group, the solvent having no methylated BSA added thereto was added in similar manner. After 1 week, blood was collected from rabbit auricular artery, and antibody titer of the blood was measured by using the ELISA procedure described in Example 6-(2) to confirm that the sensitization had been established in the antigen-sensitized group. Next, the methylated BSA was adjusted by D-PBS (pH 7.4) to 5 mg/mL, and 1 mL was administered to the knee joint cavity of the antigen-sensitized group to induce arthritis. Simultaneously, 1 mL of D-PBS (pH 7.4) was administered to the knee joint cavity of the solvent control group. 4 days and 10 days after the induction, lavage fluid of the knee joint cavity was collected from both groups, and measurement of the sCD14-ST and analysis of blood cell fraction by smearing were conducted. Simultaneously, blood was collected from auricular artery (by adding citric acid to the blood) to measure blood sCD14-ST. In the smear sample, accumulation of a large number of granulocytes was recognized in the antigen-sensitized group. In addition, when the lavage fluid of the knee joint cavity was analyzed by the sCD14-ST assay system described in Example 3-(2), increase in the sCD14-ST was recognized in the antigen-sensitized group 4 days and 10 days after the antigen sensitization as shown in
Example 7
Production of sCD14-ST Associated with the Phagocytosis of the Phagocyte from Human
(101) 7-(1) Preparation of Human Peripheral Blood Granulocyte
(102) Granulocyte fraction was prepared from peripheral blood collected from a healthy human donor by density-gradient centrifugation using two layers each having a specific gravity of d=1.077 and d=1.119.
(103) 7-(2) Production of sCD14-ST by the Phagocytosis of Granulocyte
(104) Various leukocyte stimulants were added to the granulocyte to evaluate the amount of sCD14-ST produced. More specifically, human peripheral blood granulocyte collected in Example 7-(1) was suspended in RPMI1640 culture containing 10% healthy human serum, 2 mM Glutamin, 10 mM HEPES, and 10 ng/ml G-CSF (SIGMA R8758) to a cell concentration of 0.5107 cells/mL, and added to the wells of a 96 well culture plate (Nunclon Surface, Nunc) at 100 L/well. The granulocyte was incubated overnight at 37 C. in the presence of 5% carbon dioxide. Next, various stimulants were adjusted to 1.5 fold concentration with HBSS buffer containing 10% healthy human serum, 2 mM Glutamin, and 10 mM HEPES, and added to the well at 200 L/well. After incubating at 37 C. for 2 hours, the supernatant was collected by centrifugation, and human sCD14-ST was measured by using the assay kit described in Example 7-(3) of WO 2005/108429. More specifically, the sandwich assay kit used was the one containing the antibody which binds to the peptide consisting the amino acid sequence of 53rd to 68th amino acid residue of the human CD14 (S68 antibody), which specifically recognizes the human sCD14-ST. To constitute the sandwich assay kit, another antibody which binds to the peptide consisting the amino acid sequence of 17th to 26th amino acid residue of the human CD14 (F1106-13-3), which has been labeled with peroxidase, was used. As shown in
(105) 7-(3) Action of Phagocytosis Inhibitor for the Production of sCD14-ST
(106) Action of the phagocytosis inhibitor on the sCD14-ST production by human granulocyte was examined. More specifically, human peripheral blood granulocyte was cultivated overnight on a 96 well culture plate as in the case of Example 7-(2). Next, various phagocytosis inhibitors was adjusted to 3 fold concentration with HBSS buffer containing 10% healthy human serum, 2 mM Glutamin, and 10 mM HEPES, and added to the well at 100 L/well. After incubating at 37 C. for 1 hour, 30 times by cell count of E. coli was added to the granulocyte (E. coli was added by counting 1 colony forming unit as 1 cell). After incubating at 37 C. for 2 hours, the supernatant was collected by centrifugation, and the human sCD14-ST was assayed by using the assay kit described in Example 7-(3) of WO 2005/108429. The results are shown in
(107) 7-(4) Experiment of the Phagocytosis by Using HL-60 Cell
(108) HL-60 cell was cultivated in the presence of DMSO for differentiation into granulocyte, and then used for the experiment similar to Example 7-(2). Production of the sCD14-ST by the addition of zymosan or E. coli was recognized as in the case of the Example 7-(2).
(109) The Examples as described above are some of the preferred embodiments of the present invention, and the present invention is not limited by these Examples. Various changes and modification may be made to these embodiments without deviating from the scope of the present invention.
(110) SEQUENCE LISTING