Abstract
Cell-mediated Immunity directed against simian virus 40 (SV40) tumor-specific surface antigen(s) (TSSA) was detected in SV40-immunized noninbred LVG:LAK hamsters with the use of a lymphocyte transformation assay. Sensitized spleen cells underwent a proliferative response in the presence of cells of an SV40-induced hamster sarcoma cell line (WF5-1) or the plasma membranes from these cells. In addition, 3-M KCI extracts of the plasma membranes of WF5-1 cells elicited such a lymphocyte proliferative response. Neither the cells of a chemically induced sarcoma cell line (OBT), their plasma membranes, nor 3-M KCI extracts of these membranes caused a similar proliferative response. These results established that immunization of adult hamsters with SV40 resulted in a specific autochthonous cell-mediated immune response against SV40 TSSA. The in vitro demonstration of this virus-induced immunity provided a unique method for the investigation of the SV40 TSSA Involved in the establishment or rejection of tumors. The described lymphocyte transformation assay was also used to follow the solubilization and purification of the SV40 TSSA.