Expression and thermal stability of simian virus 40 tumor-specific transplantation antigen and tumor antigen in wild type- and tsA mutant-transformed cells

Abstract

We have explored aspects of a suggested relationship between the expression of simian virus 40 tumor-specific transplantation antigen (TSTA) and tumor antigen (TA). A unique rat embryo cell line transformed by a temperaturesensitive A mutant that loses TA during exposure to the nonpermissive temperature (A28-RE) was found to lose TSTA. On the other hand, a typical control tsA-transformed cell line (A239-MB) expressed both TA and TSTA at the nonpermissive temperature. TA in lysates obtained from A239-MB cells was found to be three to four times more thermolabile by complement fixation than TA obtained from wild-type-transformed cells (SVWT-MB) when incubated at either 33 or 400C. These data complement previous reports using TA from lytic infection and are consistent with the suggestion that TA is virus encoded. In contrast to TA, which even in wild-type-transformed cells was completely destroyed in <10 min at 500C, TSTA, assayed in vivo by tumor rejection, and tumor-specific surface antigen(s) (TSSA), defined by an in vitro cytolytic assay, were thermostabile. Even after 24 h of incubation of extracts at 500C, high levels of TSTA and TSSA activity were present. Since these surface antigens when obtained from cells transformed by tsA mutants were also thermostabile, they could not be distinguished from the wild-type antigens. These results (i) indicate a coordinate expression of TA and TSTA in transformed cells; (ii) confirm that TA is virus encoded; and (iii) confirm that the antigenic and immunogenic determinants that characterize TA and TSTA activities are distinct. However, the possibility that TSTA, like TA, is of viral rather than cellular origin is not excluded. cells loses binding activity more rapidly than size defective TAs (2, 15, 32), but contain ge-TA from wild-type-transformed cells (32). We netic lesions that map within the region re-459

Subcellular distribution of simian virus 40 T antigen species in various cell lines: The 56K protein

“…Large T Ag binds to DNA (Jessel et al, 1975(Jessel et al, , 1976Tenen et al, 1975;Carroll et al, 1974a,b); this 94K dalton species in the nucleus is thought to be responsible for initiation of DNA synthesis (Kriegler et al, 1978;Jessel el al., 1976;Reed et al, 1975;Tegtmeyer, 1972) and induction and maintenance of the transformed state of the cell (Brugge and Butel, 1975;Martin and Chou, 1975;Osborne and Weber, 1975;Tegtmeyer, 1975). It has previously been shown (Anderson et al, 1977a,b, Chang et al, 1979aLuborsky et al, 1978) that partially purified SV40 T antigen preparations contain tumor-specific transplantation and surface antigen activities (TSTA and TSSA). Thus, virus-specific transplantation and surface antigens are correlates, not necessarily of tumorigenicity, but of SV40 T antigens (Kuster et al, 1977;.…”

Subcellular Localization of Simian Virus 40 Large Tumor Antigen

“…Evidence suggests that the virus-specified TSTA is inserted into surface membrane of transformed and infected cells. This antigen has the ability to induce cell-mediated rejection of a syngeneic transplant of SV40-transforned cells in animals previously immunized with live SV40 virus (17,24,28,29,57), SV40-infected cells (23,55,56), SV40-transformed cells (22,28), or solubilized total extranuclear membrane preparations from SV40-transforned cells (2,3,13,14,20,25,34,46,59).…”

Relationship between T-antigen and tumor-specific transplantation antigen in simian virus 40-transformed cells

“…The other property is that of stimulating host cell DNA synthesis (47) and possibly initiating and maintaining transformation (5,32,33). Although it appears that one polypeptide accounts for both the T-antigen and TSTA activity, the antigenic determinants for these two activities may be different, as reported previously (3,29). It is also possible that early gene products other than the 94,000-dalton T-antigen (e.g., small t-antigen) will also be shown to possess TSTA activity.…”

“…Nuclear fractions from SV40-transformed human or mouse cells are enriched in Tantigen and also in TSTA (4,39). The expression of T-antigen and TSTA is modulated coordinately in cells transformed by temperature-sensitive SV40 viruses (3,10,44). Furthernore, the SV40 T-antigen and TSTA copurify during chromatography on DEAE-cellulose and phosphocellulose and both bind to double-stranded DNA (7, 11).…”