Liposome-facilitated enhancement of in vitro immunity to human colon cancer.
Liposome-antigens, in the presence of dialyzable leukocyte extracts (DLE)(1), were tested for their ability to enhance in vitro blastogenic responses to colon tumor antigens. Liposomes made with 6:4:1 molar ratios of phosphatidylcholine, cholesterol, and phosphatidic acid and bearing human colon cancer cell antigens were shown to be immunogenic in vitro, producing specific blastogenic responses. Addition of nonimmune DLE (500 micrograms/5 X 10(5) lymphocytes) in the in vitro culture system enhanced the blastogenic response 3x over liposome-antigen alone (p less than 0.001). Immune DLE (immune to keyhole limpet hemocyanin (KLH) and tuberculin (PPD) antigens) were suppressive (p less than 0.05) in the same study. Blastogenic reactivity to KLH was also generated in nonimmune lymphocytes and enhanced by liposomes with DLE specific to KLH (p less than 0.01). Nonspecific DLE (e.g., to PPD) caused suppression of KLH-induced blastogenesis (p less than 0.05). These findings confirm and extend prior reports noting that DLEs contain both specific and nonspecific lymphocyte blastogenic factors and suggest the use of this liposome-adjuvant system for boosting tumor immune responses.
D000230:Adenocarcinoma / Q000276:immunology*; D000276:Adjuvants, Immunologic; D000951:Antigens, Neoplasm / Q000008:administration & dosage*; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology; D002478:Cells, Cultured; D003110:Colonic Neoplasms / Q000276:immunology*; D006433:Hemocyanins / Q000276:immunology; D006801:Humans; D007962:Leukocytes / Q000276:immunology; D008081:Liposomes; D008213:Lymphocyte Activation; D014373:Tuberculin / Q000276:immunology
D000276:Adjuvants, Immunologic; D000951:Antigens, Neoplasm; D008081:Liposomes; D014373:Tuberculin; D006433:Hemocyanins