Drug – bio-affecting and body treating compositions – Whole live micro-organism – cell – or virus containing – Genetically modified micro-organism – cell – or virus
Reexamination Certificate
1999-04-06
2001-11-20
Nguyen, Dave T. (Department: 1633)
Drug, bio-affecting and body treating compositions
Whole live micro-organism, cell, or virus containing
Genetically modified micro-organism, cell, or virus
C424S093210, C435S069100, C435S370000, C435S455000, C435S325000, C514S002600, C514S04400A
Reexamination Certificate
active
06319496
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to generation of human cytotoxic T-cells specific for carcinoma self-associated antigens and uses thereof, for example in epitope mapping and adoptive cell therapy.
BACKGROUND OF THE INVENTION
A number of approaches have been utilized in treating malignant growth of tissue cells in humans such as cancers. While the various approaches identified have frequently been successful in treating a particular cancer, one difficulty has been that there are numerous different cancers. Thus, drugs that treat one type of cancer, often are ineffective against a different type of cancer.
One method that attempts to overcome the difficulties resulting from the differences in cancers is immunotherapy. By such an approach, the immune system can select and create the method of treating a specific cancer. Being able to select and/or identify antigens including specific epitopes that can be used in such an approach is extremely important.
Specific peptides that bind human MHC molecules have now been identified for melanoma associated antigens. Darrow, T. L., et al.
J Immunol
142: 3329-3335, (1989); Hom, S. S., et al.
J Immunother
10: 153-164, (1991); Cox, A. L., et al.
Science
264: 716-719 (1994); Olive, D., et al.
Cancer Vaccine Symposium.
Cancer Research Institue. Oct. 3-4 (1994). MHC class I and/or class II peptide complexes have been reported as being recognized by human T-cells. The ability to activate T-cells by cytokines or co-stimutatory molecules is thus extremely important.
The identification of human carcinoma associated antigens and epitopes that might be recognized by human T-cells is also currently under active investigation. Molecules such as prostate specific antigen (PSA), [Oesterling, J. E., J Urol 145: 907-923, (1991); Peace, D. J., et al
Cancer Vaccine Symposium.
Cancer Research Institute. Oct. 3-5 (1994)], neu/c-erbB2 [Fisk, B., et al.
Int J Oncology
5: 51-63 (1994)] MUC-1 [loannides, C. G., et al.
J Immunol
151: 3693-3703, (1993)] point mutated ras [Tsang, K. Y., et al.
Vaccine Research
(in press); Jung, S., et al.
J Exp Med
173: 273-276 (1991); Fenton, S., et al.
J Natl Cancer Inst
85: 1294-1302, (1993)] point mutated p53 [Houblers, J. G. A., et al
Eur J Immunol
23: 2072-2077, (1993)] and carcinoembryonic antigen (CEA) [Kantor, J., et al.
J Natl Cancer Inst
84: 1084-1091, (1992); Kantor, J., et al
Cancer Res
52: 6917-6925, (1992); Ras, E., et al. European Immunology meeting, Barcelona, June (1994)] are among such candidates. One difficulty has been that many of these antigens are normal self-antigens, which therefore are not expected to trigger an immune response of the type needed for therapeutic approaches.
For example, while human CEA is extensively expressed on the vast majority of human colorectal, gastric and pancreatic carcinomas as well as approximately 50% of breast cancers and 70% of non-small cell lung cancers [Thompson, J. A., et al.
J Clin Lab Anal
5: 344-366, (1991)], CEA is also expressed at least to some extent on normal colon epithelium and in some fetal tissue. The CEA gene has been sequenced and shown to be part of the human immunoglobulin gene superfamily, and thus shares some homology with other molecules found on normal human tissues. Thompson, J. A., et al.
J Clin Lab Anal
5: 344-366, (1991); Oikawa, S., et al.
Biochem Biophys Res Commun
144: 634-642, (1987). At the amino acid level, CEA shares approximately 70% homology with NCA (non-specific cross reacting antigen) which is found on normal granulocytes. Thompson, J. A., et al. supra.
However, the immunogenicity of CEA in normal humans or cancer patients is at best suspect. Although several papers claim antibodies to CEA in patients, [Staab, H. J., et al
Br J Cancer
42: 26-33, (1980); Mavligit, G. M., et al.
Cancer
(Phila) 52: 146-149, (1983)] others claim these observations are artifacts [Collatz, E., et al
Int J Cancer
8: 298-303, (1971); Chester, K. A., et al
Clin Exp Immunol
58: 685-693, (1984); Ura, Y., et al.
Cancer Lett
24: 283-295, (1985)]. No reports of the presence or absence of T-cell responses to CEA exist.
There are two types of immune response—antigen specific responses producing antibodies, and cell specific responses eliciting cytotoxic T-cells.
Improved methods for eliciting an immune response to self-antigen would be extremely useful.
For example, cytotoxic T-cells elicited by a self-antigen can be used in somatic cell therapy, in identifying epitopes and small peptides that induce a cytoxic T-cell response and in drug assays for compounds that enhance a specific cytoxic T-cell response.
The availability of human cytotoxic T-cells specific for carcinoma self-associated antigens also allow for mapping of the epitopes recognized by the T-cells. These epitopes can in turn be used to prime or boost the immune-system to expand the T-cell population either in vivo or in vitro. The in vitro cells as aforesaid can then be transferred back into a patient as is currently done in TIL cell therapy and used to treat a tumor expressing the antigen.
SUMMARY OF THE INVENTION
We have discovered that by using a recombinant DNA viral vector, preferably a pox virus vector having at least one insertion site containing a DNA segment encoding the carcinoma self-associated antigen, or a cytotoxic T-cell eliciting epitope thereof, operably linked to a promoter capable of expression in the host, human cytotoxic T-cells specific for the carcinoma self-associated antigens can be produced. The method preferably comprises introducing a sufficient amount of the recombinant pox virus vector into a host to stimulate production of cytotoxic T-cells, and contacting the host with additional antigen at periodic intervals thereafter. The additional antigen may be added by using a second pox virus vector from a different pox genus. In another embodiment, additional antigen is added by contacting the host with antigen. The antigen may be formulated with an adjuvant or in a liposomal formulation.
We have also discovered that human cytotoxic T-cells specific for carcinoma self-associated antigens can be produced using a cytotoxic T-cell eliciting epitope of the carcinoma self-associated antigen. The method preferably comprises introducing the T-cell eliciting epitope into a host to stimulate production of cytotoxic T-cells. If necessary, in order to boost production of the cytotoxic T-cells, at periodic intervals thereafter, the host is contacted with additional T-cell eliciting epitope. The epitope may be formulated with adjuvant or may be in a liposomal formulation. Alternatively, additional T-cell elicting epitope may be added using a pox virus vector.
Carcinoma self-associated antigens include, for example, carcinoembryonic antigen (CEA), prostate specific antigen (PSA), TAG-72, IL-2r and neulc-erbB-2. CEA is preferred.
Cytotoxic T-cell eliciting epitopes of the carcinoma self-associated antigens may also be used. For CEA, preferred epitopes comprise peptides represented in the Sequence Listing as SEQ ID NO:1, 2, 3, 4, 5, 6, 7, 8, 9 and 10.
The pox virus is preferably selected from the group of pox viruses consisting of suipox, avipox, capripox and orthopox virus. Preferred orthopox include vaccinia, rabbitpox and racoon pox. Preferred avipox includes fowlpox, canary pox and pigeon pox. A more preferred avipox is fowlpox. The preferred suipox is swinepox.
Vaccinia viral vectors may elicit a strong antibody response, thus while numerous boosts with vaccinia vectors are possible, its repeated use is not preferred. We have discovered that by using pox from different genera to boost, this sensitivity problem can be minimized. In accordance with the present invention, in order to avoid such problems, preferably, when the first or initial pox virus vector is vaccinia, the second and subsequent pox virus vectors are selected from the pox viruses from a different genus such as suipox, avipox, capripox other than vaccinia.
Adjuvants incl
Panicali Dennis L.
Schlom Jeffrey
Nguyen Dave T.
Nixon & Peabody LLP
Therion Biologics Corporation
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