REJECTION OF PARENTAL METH-A TUMOR ON CONCOMITANT INOCULATION OF METH-A CELLS INFECTED RETROVIRALLY WITH THE INTERFERON-GAMMA GENE INTO (BALB CXC57BL/6)F-1 MICE/

The IFN-gamma gene was introduced retrovirally into Meth A cells. IFN- gamma gene infected Meth A (K gamma) cells were highly antigenic and r egressed in CB6F(1) mice. Concomitant immunization of CB6F(1), mice wi th IFN-gamma gene infected Meth A (K gamma) cells after inoculation of parental Meth A protected the mice from parental tumor growth. 1x10(6 ) infectant Meth A (K gamma) cells protected the mice from growth of 1 x10(6) parental Meth A cells, but 2x10(6) infectant cells did not, sug gesting that there was an optimal dose of infectant cells for rejectio n of the parental tumor. Specificity analysis revealed that growth of CMS13 tumor was slightly inhibited by Meth A (K gamma) cells but that of CMS5 was not inhibited. The findings are consistent to those obtain ed with parental Meth A cells and indicated that the relevant rejectio n antigen on Meth A (K gamma) cells was identical to the parental Meth A rejection antigen.