Feline leukemia and sarcoma viruses: susceptibility of human cells to infection

Human embryonic cells are highly susceptible to infection with feline leukemia and sarcoma viruses. These viruses were propagated in human cultures without antigenic modification or loss of infectivity for cat or human cells. Virus stocks contained at least 10(6) infectious units of virus per milliliter for human cells. Virus present in 10(-6) dilution of virus stock replicated to detectable amounts as early as 7 days after virus infection. The feline sarcoma virus induced morphological transformation of human cells.