title: Immune response of BALB/c X DBA/2F1 mice to a tumor allograft during pyran copolymer-induced tumor enhancement.
abstract: The immune response of BALB/c x DBA/2 F1 mice to a transplantable Moloney leukemia virus-induced tumor allograft (MBL-2) was studied to determine the mechanism of pyran copolymer-induced tumor enhancement. The relative levels of humoral, lymphocyte, and macrophage response were followed chronologically by in vitro cytotoxic microassays using 51Cr-labeled target cells. Although pyran increased the titer of humoral cytotoxic antibody, levels of humoral factors capable of abrogating lymphocytoxicity were not enhanced. Furthermore, splenic lymphocyte-mediated cytotoxicity, although slightly diminished in pyran-treated mice, was not significantly affected. Macrophages harvested from allograft-bearing animals exhibited marked tumoricidal activity, which was augmented by pyran treatment. This macrophage-associated activity was specific for MBL-2 cells and not attributable to cytotoxins elaborated into the culture medium. Pyran slightly activated macrophages from nonsensitized mice to become cytotoxic for MBL-2 cells; activation was not T-cell dependent. However, strikingly fewer macrophages infiltrated the allograft in pyran-treated animals as judged by both histopathology and direct measurement. The defect in the migration or deposit of macrophages at the allograft site may have contributed to tumor enhancement.
mesh_terms: D000818:Animals; D000906:Antibodies; D000917:Antibody Formation; D001202:Ascitic Fluid / Q000166:cytology; D002465:Cell Movement / Q000187:drug effects; D003165:Complement System Proteins / Q000032:analysis; D003601:Cytotoxicity Tests, Immunologic; D006084:Graft Rejection; D007942:Leukemia, Experimental / Q000276:immunology* / Q000473:pathology; D008214:Lymphocytes / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009368:Neoplasm Transplantation; D011108:Polymers / Q000494:pharmacology*; D011713:Pyran Copolymer / Q000494:pharmacology*; D013154:Spleen / Q000276:immunology; D014184:Transplantation, Homologous
chemical_list: D000906:Antibodies; D011108:Polymers; D011713:Pyran Copolymer; D003165:Complement System Proteins