Antitumor efficacy of two kinds of tumor vaccine modified with vaccinia virus.

We compared antitumor effectiveness of two types of tumor vaccine modified with vaccinia virus (VV). One type is UV-inactivated VV (UV-VV) -absorbed tumor cell vaccine (UV-VV TCV) produced by tumor cells that had been absorbed in vitro with UV-VV and subsequently X-irradiated with 10(4) rads. The other type is vaccinia oncolysate vaccine (VOV) from tumor cells that had been infected in vitro with live VV and subsequently sonicated. C3H/HeN mice were inoculated i.p. with UV-VV after whole body X-irradiation with 150 rads. After 3 weeks, the two kinds of vaccine were administered i.p. 3 times at weekly intervals. One week after the last injection, mice were challenged i.p. with syngeneic MH134 or X5563 viable tumor cells at different doses. The fifty percent tumor lethal doses (TLD50) of MH134 in mice treated with UV-VV TCV and VOV were 10(6.6) and 10(5.3), respectively, whereas the TLD50 of MH134 in non-treated mice was 10(0.6). The TLD50 of X5563 in mice treated with UV-VV TCV and VOV were 10(6.5) and 10(4.4), respectively, while the TLD50 of X5563 in non-treated mice was 10(0.5). These results show that UV-VV TCV is more effective than VOV. We suggest that the complete cell structure of the vaccine is more effective for enhancing tumor immunity.