Twelve percent of women in the United States will develop invasive breast cancer, and the incidence of the disease is increasing. In spite of these alarming statistics, few new modalities are being applied to the treatment of mammary adenocarcinoma. The transfer of lymphoid effector cells with antitumor reactivity to tumor-bearing hosts is a relatively new approach to the treatment of advanced cancer. Such adoptive immunotherapy (AI) is being attempted with several distinct populations of lymphocytes with varying degrees of success. One such population consists of lymphocytes that infiltrate into growing cancers. While tumor-infiltrating lymphocytes (TILs) appear to be the most appropriate effector cells for this purpose, few attempts have been made to treat breast cancer patients by means of AI with TILs. The usual sequence in the development of a therapeutic modality is to demonstrate efficacy in an animal model prior to initiating human studies. Thus, the major objective of my laboratory is to establish spontaneous mouse mammary tumors as a model system with which to test the therapeutic potential of TILs against mammary adenocarcinoma. To this end, we are attempting to do the following: (1) Optimize the culture conditions for activation and large-scale expansion of mouse mammary tumor TILs. The following approaches to this problem are being evaluated: stimulation with non-specific mitogens, culture in the presence of interleukin-2 (IL-2) and irradiated autologous tumor cells, simultaneous stimulation by rIL-2 and immobilized anti-CD3 monoclonal antibody, addition of tumor necrosis factor a to the culture medium, augmentation of the stimulating effect of IL-2 with interferon a, non-specific propagation with surface-oxidized stimulator cells, and inhibition of suppressor T cell activity with mafosfamide. (2) Identify the TIL subset with maximum cytolytic activity. This will be done by using flow cytometry to sort bulk TIL cultures followed by in vitro cytotoxicity assays on each subpopulation. Another approach to this problem will be to use depletion techniques with antibody and complement followed by cytotoxicity assays. (3) Assess and compare the stages of the lytic sequence independently for each population of cells. This will be accomplished by combining a standard 51Cr-release cytotoxicity assay with an agarose single cell cytotoxicity assay. (4) Evaluate the therapeutic efficacy of TILs against spontaneous mouse mammary adenocarcinomas. We will adoptively transfer TILs prepared from mammary tumors and expanded in long-term culture into syngeneic mice bearing spontaneous mammary tumors and determine the response of the tumors and the survival of the recipient animals.
Ames, I. H., G. M. Gagne, D. L. Weiner, and D. G. Tice 1994 Characterization of tumor-infiltrating lymphocytes from murine mammary adenocarcinomas. Anticancer Research, 14: 881-888.
Ames, I. H., G. M. Gagne, A. M. Garcia, P. A. John, G. M. Scatorchia, R. H. Tomar, and J. G. McAfee 1989 Preferential homing of tumor-infiltrating lymphocytes in tumor-bearing mice. Cancer Immunology and Immunotherapy, 29: 93-100.
Ames, I.H., C.E. Gates, A.M. Garcia, P.A. John, A.K. Hennig, and R.H. Tomar 1987 Lysis of fresh murine mammary tumor cells by syngeneic natural killer cells and lymphokine activated killer cells. Caner Immunology and Immunotherapy, 25: 161-168.
Ames, I.H., A.M. Garcia, P.A. John, C.A. Litty, M.A. Farrell, and R.H. Tomar 1986 Decreased natural cytotoxicity in mice with high incidence of mammary adenocarcinomas. Clinical Immunology and Immunopathology, 38: 265-273.
Ames, I.H., E. Spring-Mills, M.A. Downing, and M. Bush 1984 Fine structure analysis and surface characteristics of mouse mammary gland adenocarcinomas. Scanning Electron Microscopy, I: 391-399.