Lack of expressions of endogenous (gs, chick helper factor) and exogenous avian RNA tumor viruses in the MOB-1 and MSB-1 lines derived from Marek's disease lymphomas.

Lack of expressions of endogenous (gs, chick helper factor) and exogenous avian RNA tumor viruses in the MOB-1 and MSB-1 lines derived from Marek's disease lymphomas.