Effect of indomethacin on tumor-infiltrating lymphocytes of a spontaneously developed murine mammary adenocarcinoma.
The effect of indomethacin on tumor-infiltrating lymphocytes (TIL) was investigated in a spontaneously developed and weakly immunogenic murine mammary adenocarcinoma (designated JC) in syngeneic immunocompetent BALB/c mice, a tumor model mimicking human disease. Unlike other chemically and virally induced tumors, the expansion of TIL was only possible with an enriched population of lymphocytes, isolated on a discontinuous density gradient then cultured in complete medium containing recombinant human interleukin-2 (rIL-2). The freshly isolated TIL exhibited no cytotoxicity against either the natural-killer-sensitive YAC-1 or the natural-killer-resistant JC cells lines. After culture in rIL-2, the TIL of the JC tumor lysed both YAC-1 and JC. The cytotoxicity of the TIL reached a maximum between the 2nd and 3rd week of culture and decreased thereafter. Antibody- and complement-depletion tests revealed that the cells bearing asialo-GM1 antigen represented the major precursor cells of the cytotoxic TIL, which may explain its nonspecific cytotoxicity. Indomethacin was shown to accelerate the cell proliferation of the rIL-2-activated TIL, but only in the initial 2 weeks of culture and not in later culture. The addition of indomethacin to the rIL-2-containing medium at the beginning of culture resulted in a fast-acting and long-lasting enhancement in cytotoxicity. These results provided a basis for the clinical use of indomethacin, i.e. acceleration in proliferation and augmentation in cytotoxicity. However, the addition of indomethacin at the end of the fourth week after rIL-2 culturing produced neither accelerated proliferation nor augmented cytotoxicity. This study also suggested that a prolonged administration of indomethacin may not be advantageous in clinical trials, since the long-term continuous presence of indomethacin in the culture has resulted in a negative effect on the growth of TIL.
Chao
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Department of Diagnostic Immunology Research and Biochemistry, Roswell Park Memorial Institute, Buffalo, NY 14263.
Chu
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D000230:Adenocarcinoma / Q000276:immunology*; D000818:Animals; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D005260:Female; D005677:G(M1) Ganglioside; D006028:Glycosphingolipids / Q000032:analysis; D007213:Indomethacin / Q000494:pharmacology*; D007376:Interleukin-2 / Q000494:pharmacology; D008214:Lymphocytes / Q000187:drug effects* / Q000276:immunology; D015674:Mammary Neoplasms, Animal / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010641:Phenotype; D011994:Recombinant Proteins / Q000494:pharmacology
D006028:Glycosphingolipids; D007376:Interleukin-2; D011994:Recombinant Proteins; D005677:G(M1) Ganglioside; C018835:asialo GM1 ganglioside; D007213:Indomethacin