Regressing Friend Leukemia Virus

**Semantic type:** Virus

**Definition:** Animals inoculated with the regressing strain of Friend virus exhibited an initial pathologic response identical to that induced by conventional strains of Friend virus. Unlike the fatal leukemia produced by conventional Friend virus, the pathology of the disease induced by the regressing strain of Friend virus regresses in 50% of leukemic mice.

**Synonyms:** - CFV - Friend Leukemia Virus, Regressing - Regressing FV