title: Highly malignant tumor variants retain tumor-specific antigens recognized by T helper cells.
abstract: We have studied the components of a complex of tumor-specific antigens to determine if all of the components of the complex were lost during progression from a rather benign regressor tumor to a highly malignant (HM) cancer. We find that the HM tumor cells have lost antigens recognized by CTL but retained antigens recognized by Th cells. Immunization with variants expressing Th-defined antigens induced tumor-specific immunity to challenge with a parental variant that expressed a CTL-recognized target antigen, but did not induce immunity to challenge with the variant that expressed the Th-defined antigen alone. Together, these findings suggested that Th cells fail to exert direct selective pressure upon the tumor, resulting in retention of "lineage-specific," Th-recognized antigens by highly immunoselected variants. Possible advantage could be taken of this fact for the development of specific immunotherapy.
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000032:analysis* / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D005260:Female; D006968:Hypersensitivity, Delayed; D007114:Immunization; D051379:Mice; D008809:Mice, Inbred C3H; D009374:Neoplasms, Experimental / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D000951:Antigens, Neoplasm