Tumor development and induction of resistance by Rous sarcoma virus in Japanese quail.

Response of Japanese quails to an inoculation of Schmidt-Ruppin strain of Rous sarcoma virus (SR-RSV) was examined. The quails were as susceptible as chick embryo cells to the infection of SR-RSV. The tumors induced in the quails contained a significant amount of infectious virus and avian leukosis group-specific CF antigen at early stages of 1 to 3 weeks after inoculation, but they turned to be noninf ective at the late stage with a concomitant disappearance of CF antigen. High incidence of regression was observed with the tumors induced by a low dose of virus, while the tumors induced by a high dose rarely regressed. The quails became resistant to a subsequent challenge following a primary inoculation of the virus. The resistant state was established about 10 days after a primary inoculation, and was specifically induced by infectious SR-RSV. An association of virus neutralizing antibody or interferon in the resistant state was not demonstrated. Possibility of a participation of cellular immunity in the induction of resistance was discussed.