THE ENVELOPES OF 2 ECOTROPIC MURINE LEUKEMIA VIRUSES DISPLAY DISTINCTEFFICIENCIES IN RETROVIRAL VACCINATION BY INTERFERENCE

In cell cultures infected with a retrovirus, the expression of the vir al envelope interferes with superinfection by retroviruses which recog nize the same receptor. We have previously demonstrated that vaccinati on of susceptible strains of mice (of the Mus musculus species) with t he attenuated ecotropic Friend murine leukemia virus (F-MuLV) B3 effic iently protects against the early hemolytic anemia and the erythroleuk emia induced by a challenge with the virulent F-MuLV 57 through a simi lar in vivo mechanism of interference to superinfection (A. Corbin and M. Sitbon, J. Virol. 67, 5146-5152, 1993), Vaccination with the heter ologous ecotropic Moloney-MuLV (M-MuLV) efficiently protects against t he early hemolytic anemia but has a weak protective effect on the F-MU LV 57-induced erythroleukemia. Furthermore, vaccination with the atten uated F-MuLV B3 had only a transient protective effect on M-MuLV-induc ed thymomas. These different efficiencies of F- and M-MuLV to confer p rotection in this model of vaccination by interference were mostly due to envelope sequences, indicative of distinct in vivo interference pr operties of the two ecotropic envelopes. (C) 1994 Academic Press, Inc.