| Abstract: | Marked differences in the manifestation of SV40-specific surface (S-) antigen were found between hamster cell lines transformed in vitro and in vivo by SV40 and UV-irradiated or photodynamically inactivated SV40. In the mixed hemagglutination reaction (MHA) cell lines induced by non-irradiated SV40 yielded positive results when tested against specific antisera up to dilutions of 1:1280. In comparison, cell lines induced by inactivated SV40 only showed positive reactions in the MHA-test in dilutions up to 1:80 or 1:160 respectively. The demonstration of small quantities of SV40-specific S-antigen in cell lines transformed by inactivated SV40 could only be achieved by use of hyperimmune sera produced by a special immunization procedure. However, if these cells were tested in the MHA reaction against anti-S-sera, produced according to conventional methods described in the literature, they yielded negative results. All cell lines with diminished quantities of demonstrable S-antigen caused malignant tumors when inoculated into adult hamsters. The capacity of UV-irradiated SV40 to induce a specific transplantation resistance in adult Syrian hamsters was investigated. The irradiated virus induced a markedly reduced transplantation resistance. |
