XENOGENIC NORMAL TISSUE-DERIVED VACCINES FOR BREAKING THE IMMUNE TOLERANCE TO TUMOR-ASSOCIATED, ANTIGENS

Abstract

Disclosed is an antitumor vaccine including testicular and fetal tissue-derived components. Cell preparations are prepared from normal tissues harvested directly from animals. Such vaccines may be used in the treatment and prevention of different cancers. For example, a vaccine consisting of glutaraldehyde-treated cells prepared from sheep testis and fetal lung has been found to be effective in inducing antitumor cell-mediated responses, as well as in prolonging the survival of mice with lung cancer.

Claims

1-22. (canceled)

23. A composition comprising xenogenic adult-derived cells and xenogenic fetal tissue-derived cells.

24. A composition according to claim 23, wherein the tumor specificity of said composition is determined by xenogenic fetal tissue-derived cells component.

25. A composition according to claim 24, for use in the treatment or prevention of a lung tumor, the composition comprising adult testis-derived and fetal lung tissue-derived cells.

26. A composition according to claim 23, wherein intact whole cells are used.

27. A composition according to claim 23, wherein fixed whole cells are used.

28. A composition according to claim 27, wherein the cells are fixed with glutaraldehyde.

29. A composition according to claim 23, wherein intact cell lysates are used.

30. A composition according to claim 23, wherein lyophilized cell lysates are used.

31. A composition according to claim 23, wherein said cells are derived from a mammal.

32. A composition according to claim 31, wherein said mammal is sheep, pig, cat or mouse.

33. A composition comprising xenogenic adult-derived cells and xenogenic fetal tissue-derived cells for use in the treatment or prevention of a tumor in a patient.

34. A method for breaking immune tolerance to tissue-specific differentiation antigens, comprising providing the xenogenic composition of claim 23, and administering an effective amount of the xenogenic composition.

35. A method for cancer treatment in patients in the circumstances when tumor-affected organ preservation is not necessary, comprising providing the xenogenic composition of claim 23, and administering an effective amount of the xenogenic composition.

36. A medicament for treatment or prevention of a tumor in a patient comprising the composition according to claim 23.

37. A method for breaking immune tolerance to tissue-specific differentiation antigens, comprising providing the xenogenic composition of claim 23, and administering an effective amount of the xenogenic composition.

38. A method for breaking immune tolerance to tissue-specific differentiation antigens, comprising providing the xenogenic composition of claim 24, and administering an effective amount of the xenogenic composition.

39. A method for breaking immune tolerance to tissue-specific differentiation antigens, comprising providing the xenogenic composition of claim 25, and administering an effective amount of the xenogenic composition.

40. A method for breaking immune tolerance to tissue-specific differentiation antigens, comprising providing the xenogenic composition of claim 26, and administering an effective amount of the xenogenic composition.

41. A method for breaking immune tolerance to tissue-specific differentiation antigens, comprising providing the xenogenic composition of claim 27, and administering an effective amount of the xenogenic composition.

42. A method for breaking immune tolerance to tissue-specific differentiation antigens, comprising providing the xenogenic composition of claim 28, and administering an effective amount of the xenogenic composition.

Description

SHORT DESCRIPTION OF DRAWINGS

[0014] FIG. 1. Shows leukocyte infiltration of a tumor in the control and vaccinated mice, where “**” marks P<0.05 compared to the control in this and other figures.

[0015] FIG. 2. Shows LLC antigen-induced production of IL-2 by the spleen cells isolated from the control and vaccinated mice.

[0016] FIG. 3. Shows the median survival of the control and vaccinated mice.

DESCRIPTION OF THE INVENTION

[0017] The present invention is directed to overcoming the preexisting immune tolerance to tumor-associated, differentiation antigens. A xenogeneic vaccine is provided that comprises components derived from normal tissue harvested from one species of a mammal to prevent or treat tumors in a mammal of another species. The objects of this invention are vaccine compositions comprising xenogenic testicular cells and xenogenic tissue-derived cells. It is suggested that such vaccine compositions can be useful for treating numerous cancers and have apparent advantages over all previously described vaccines. They are much more immunogenic compared to autological or allogeneic analogs. They induce polyclonal immune responses and therefore are more effective in tumor growth inhibition in comparison with peptide-based vaccines capable of inducing only oligoclonal immune reactions.

[0018] Very important advantage of the xenogenic normal tissue-derived vaccines of the invention is the use of unlimited and reproducible sources for their manufacturing. Numerous amounts of testicular and tissue-derived cells can be obtained from a chosen mammal source. Preferably, said mammal is sheep, pig, cat or mouse. Most preferred animal source is a sheep.

[0019] The vaccine compositions will usually comprise testicular and fetal tissue-derived cells from the same xenogenic species; however, in some embodiments, testicular cells from a first xenogenic species and tissue-derived cells from a second xenogenic species may be used, for example testicular cells from a sheep and tissue-derived cells from a pig, or vice-versa.

[0020] The amounts of the components of the vaccine composition will be apparent to the skilled person. The preferred ratio of testicular and tissue-derived cells in the vaccine composition is from 1:10 to 10:1; more preferred ratio is from 1:5 to 5:1; most preferred ratio is 1:1.

[0021] The current invention provides a possibility to manufacture a number of vaccines useful for treating different cancer types. Each specialized vaccine is achieved by a combination of common (shared) and tissue-specific TAAs. For example, a vaccine composition for lung cancer may comprise testicular cells and lung tissue-derived cells; a vaccine composition for renal cancer may consist of testicular cells and fetal renal tissue-derived cells; and so on. The vaccine composition for lung cancer is preferred. It should be noted that animal fetal tissues can be sources of not only tissue-specific, both also common differentiation antigens.

[0022] In some embodiments, the said vaccine composition is described as a heterologous mixture of antigens presented by whole tissue cells that were processed with glutaraldehyde. Other substances can be used for fixation and preservation of the cells, such as formaldehyde and alcohol. Vaccines may be also used in the form of intact or lyophilized cell lysates. The present invention provides a pharmaceutical composition comprising a therapeutically effective amount of xenogenic testicular cells and xenogenic fetal tissue-derived cells. The pharmaceutical compositions may be for human or animal usage in human and veterinary medicine.

EXAMPLES

Materials and Methods

Mice.

[0023] C57BL/6 (B6; H-2.sup.b) mice were bred in our own facilities. The mice were male and of ages ranging between 4 and 6 months. They received autoclaved food and boiled water.

Tumor Cell Line.

[0024] LLC carcinoma cell line of B6 (H-2.sup.b) origin has been obtained from Moscow Oncologic Scientific Center of Russian Academy of Medical Sciences and was maintained in RPMI 1640 medium supplemented with 10% FCS, 2 mM 1-glutamine, and antibiotics.

Preparation of the Tumor Cell Lysate for Immunoreactivity Assay.

[0025] LLC cells were harvested, washed extensively with phosphate-buffered saline (PBS) and further stored at −20° C. until use.

Preparation of Vaccinal Components.

[0026] Testis were isolated from the adult sheep. After being released from its capsules, the spermatogenous tissue was fragmented with scissors and then suspended with the aid of a glass homogenizer using gentle pressing of tissue fragments in the cold PBS. The cell suspension was stayed for 7 min to sediment large aggregates. After being transferred from the homogenizer into a tube, the cells were washed with the cold PBS. Next, a portion of the cells was incubated in 0.1% glutaraldehyde (v/v) at 37° C. for 20 minutes and then extensively washed to produce a vaccinal cell preparation. Another cell portion underwent a procedure of freezing and thawing three times and was then centrifuged to obtain the supernatant containing soluble testicular antigens.

[0027] The lungs were isolated from the sheep fetuses at 3 to 4 months of age. The isolated lungs were extensively washed within a large volume of cold PBS and then fragmented with scissors. The cells were gently squeezed out from the lung fragments into the cold PBS and transferred into a tube. The vaccinal glutaraldehyde-treated lung cells and the supernatant containing soluble lung antigens were prepared essentially as described above.

Tumor Implantation and Vaccination Procedures.

[0028] Five groups of B6 male mice, each of which consisted of 15 animals, were established. All mice were injected with LLC cells (2×10.sup.5/mouse) subcutaneously (s.c.) on day 0.

1. The control group. The mice did not undergo any immunization.
2. The group vaccinated with xenogenic testis cells. The mice were subcutaneously immunized with glutaraldehyde-treated testis cells on day 3, 7, and 11 at a dose of 2×10.sup.6, 4×10.sup.6, and 6×10.sup.6/mouse, respectively.
3. The group vaccinated with xenogenic lung cells. The mice were immunized with glutaraldehyde-treated lung cells on day 3, 7, and 11 at a dose of 2×10.sup.6, 4×10.sup.6, and 6×10.sup.6/mouse, respectively.
4. The group vaccinated with xenogenic testis and lung cells. The mice received immunizations with glutaraldehyde-treated testis and lung cells at a dose of 1×10.sup.6, 2×10.sup.6, and 3×10.sup.6/mouse for each kind of cells on day 3, 7, and 11, respectively.
5. The group vaccinated with xenogenic soluble testicular and lung antigens. The mice were immunized thrice with a mixture of soluble testis and lung products at the amounts equivalent the vaccinal cells used in the fourth group.

Immunoreactivity Analysis.

[0029] Five mice from each group were analysed for immunoreactivity to LLC carcinoma antigens at day 18 after tumor implantation. For histological examinations, the microscopic sections of a thickness of 5-to-7 μm were stained with a hematoxylin-eosin. The degree of leukocyte infiltration was scored from 0 to 5. For T-cell reactivity assay, the spleens were suspended with the aid of a glass homogenizer. The cell suspensions were stayed for 7 min to seat down large aggregates and the single-cell suspensions were then transferred from the homogenizer into a tube. After being extensively washed with the cold medium, spleen cells were cultured at 2×10.sup.5/well with lysates of LLC cells (each 5×10.sup.4/well), or without them in control, in a 96-well round-bottom plate in serum-free medium for 3 days. Amounts of interleukin-2 (IL-2) in the cultural supernatants were assessed using commercially available enzyme-linked immunosorbent assays (ELISA). Stimulation index was calculated as follows: test IL-2 level/control IL-2 level.

Survival Registration.

[0030] Mice were observed daily for survival and dead animals were autopsied. Evidence of tumors was grossly detected with clearly visible metastasis process.

Statistics.

[0031] The statistical significance of the data was determined using the Student's test. A P-value of <0.05 was considered to be statistically significant. The Kaplane-Meier method was employed to estimate overall survival.

Example 1

[0032] Vaccinations with Xenogenic Tissue-Derived Cells Stimulate Infiltration of the Tumor with Leukocytes

[0033] The inflammatory response at the tumor margin was evaluated by enumerating mononuclear and granulocytic cells over ten high-powered (40× objective) fields. As can be seen in FIG. 1, xenovaccinations of tumor-bearing mice with either testis or lung cells, as well as a mixture of those cells induced a marked leukocyte infiltration of the tumor, whereas vaccinations with soluble xenogenic antigens have no such an effect. The detected inflammatory responses were composed of eosinophils (nearly 20%), neutrophils (40%), lymphocytes (30%) and macrophages (10%). The marked tumor-associated tissue eosinophilia at the tumor margins of cell-vaccinated mice distinguishes those inflammatory responses from that observed in the tumors of control mice. A tumor-associated eosinophilic infiltrate has been shown to be a favorable prognostic indicator in colorectal carcinoma and early esophageal squamous cell carcinoma (FemandeZ-Acemo, et. al., 2000; OhashiY et. al. 2000). Activated eosinophils or their culture supernatants were found to be capable of inhibiting significantly the growth of the cultured human prostate cancer cells (Furber't-Harris et. al., 2003). A possible role for eosinophils in the protective immune response conferred by cell-based xenovaccination could exist in our own experiments.

Example 2

[0034] Vaccinations with Xenogenic Tissue-Derived Cells Induce Immune Reactivity to Tumor Cells.

[0035] The present example demonstrates that immunization with xenogenic tissue-derived cells is able to induce antitumor T-reactivity evidenced by producing interleukin-2 (IL-2). IL-2 is well known to be a pivotal mediator in the mechanism of generating the long-lasting adaptive immunity. As shown in FIG. 2, soluble xenogenic (testicular plus lung) antigens failed to induce T-cell reactivity to LLC antigens in tumor-bearing mice. Adjuvants appear to be required to render xenogenic soluble antigens capable of inducing immune responses with a notable efficiency. In contrast to the soluble antigens, both testis and lung cells were able to induce detectable antitumor reactivity (p<0.05 compared to control). Noteworthy that the combined vaccinations with testis and lung cells were more effective in this regard compared to vaccinations with either testis cells or lung cells alone.

Example 3

[0036] Vaccinations with Xenogenic Tissue-Derived Cells Prolong Survival of Tumor-Bearing Mice.

[0037] As can be seen in FIG. 3, the median survival in LLC-bearing —bearing mice vaccinated with a combination of xenogenic testis and lung cells was significantly longer (P<0.05) than was the control LLC-bearing mice. The vaccinations with either testis cells or lung cells alone barely slightly prolong the survival LLC-bearing mice. Xenogenic soluble antigens were ineffective in this regard. From these data it may be concluded that 1) in the absence of immunoadjuvants the xenogenic tissue-derived cells are much more effective as a cancer vaccine, than are xenogenic soluble antigens of the same origin; and 2) antitumor clinical responses may be largely potentiated by combining vaccinal cells, expressing common (for example testicular) and fetal tissue-specific (for example fetal lung) antigens which may express in tumor cells.

REFERENCES

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