Adoptive immunotherapy of syngeneic murine leukemia is enhanced by the combination of recombinant IFN-gamma and a tumor-specific cytotoxic T cell clone.
Mice with an established syngeneic T cell tumor (RBL5) received short term adoptive chemoimmunotherapy with CTL clone 1.B6 and murine rIFN-gamma. In comparison with treatment with either agent alone, the combination of 1.B6 and rIFN-gamma was associated with a dramatic increase in long term survival. No direct effects of rIFN-gamma on tumor cell proliferation, MHC Ag expression, or susceptibility to CTL-mediated lysis could be demonstrated to explain the prolongation of survival. However, rIFN-gamma induced a distinct increase in broad-spectrum cytolytic capacity of peritoneal exudate cells and further increased class II MHC expression on peritoneal macrophages. The explanation for enhanced adoptive chemoimmunotherapy after combined short term administration of a CTL clone and rIFN-gamma is uncertain. Potential mechanisms include direct tumor lysis by activated cells, indirect tumor lysis via sensitization to other lymphokines or monokines, improved Ag-specific activation of transferred CTL clones, and/or more effective development of de novo host anti-tumor immunity.
D000818:Animals; D002999:Clone Cells / Q000276:immunology / Q000637:transplantation; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D007116:Immunization, Passive; D007371:Interferon-gamma / Q000494:pharmacology / Q000627:therapeutic use*; D007942:Leukemia, Experimental / Q000276:immunology / Q000628:therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D010529:Peritoneal Cavity / Q000473:pathology; D011994:Recombinant Proteins / Q000494:pharmacology / Q000627:therapeutic use; D013268:Stimulation, Chemical; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000637:transplantation*
D000949:Histocompatibility Antigens Class II; D011994:Recombinant Proteins; D007371:Interferon-gamma