Tumor-specific transplantation antigen: use of the Ad2+ND1 hybrid virus to identify the protein responsible for simian virus 40 tumor rejection and its genetic origin.

Abstract

Cells transformed by SV-40 possess a tumor-specific transplantation antigen (TSTA) that has the property of immunizing animals against syngeneic tumor challenge. The early SV-40 DNA segment present in the human adenovirus 2 (Ad2)-SV-40 hybrid, Ad2+ND1, is sufficient to induce this SV-40-specific TSTA in BALB/c mice. Studies on the intracellular distribution of TSTA activity in Ad2+ND1-infected cells, as determined by the ability of various subcellular fractions to immunize mice against syngeneic tumor challenge, suggested a correlation between this biological activity and the presence of the SV-40-specific 28,000 M protein coded by this hybrid virus. Both the TSTA activity and the 28,000 MW protein are found in the plasma membrane fraction and in the perinuclear region of infected cells but are virtually undetectable in the cytoplasmic fraction. Using a hamster antitumor antiserum that can specifically immunoprecipitate the 28,000 MW protein, a loss of TSTA activity concomitant with the removal of this SV-40-coded protein was demonstrated. Thus, it appears that antigenic determinants responsible for SV-40-specific tumor rejection in mice are contained within the 28,000 MW protein coded for by the early SV-40 DNA segment that extends from 0.17-0.28 map unit.