In vitro host range of equine infectious anemia virus.

Equine infectious anemia virus (EIAV) was successfully inoculated onto cell cultures of canine and feline origin, resulting in chronic infections in these cultures. Infection of equine cell cultures, which were the previous sole in vitro source demonstrated for virus production, was also performed for comparative purposes. Determination of the nature of the virus produced in the heterologous as well as the equine cells was accomplished in several ways. SDS-PAGE of purified virus from the different cell lines indicated very similar protein composition. Immunological identity was observed in gel diffusion tests employing an antiserum to the major core protein (p24) of equine-derived EIAV. Competition radioimmunoassays also indicated similar antigenicity in the viruses derived from the several cell lines. Strong relatedness was further demonstrated by hybridization of viral RNAs to EIAV complementary DNA. These data indicate that EIAV has an amphotropic cell culture host range and that the viruses isolated from the permissive lines were similar.

Large-scale production of mouse mammary tumor virus in the absence of endogenous murine leukemia virus.

A system for the large-scale production and purification of mouse mammary tumor virus in the absence of detectable endogenous murine leukemia virus is described. By utilizing the Mm5mt/c1 cell line established from an adenocarcinoma of a C3H mouse, the continuous production of over 25,000 liters of mouse mammary tumor virus-containing tissue culture fluids has been achieved. By the strict adherence to well-defined tissue culture conditions, mammary tumor virus production was accomplished without the expression of murine leukemia virus. Various biochemical and immunological systems were established for the rapid and precise detection of the endogenous leukemia virus, the expression of which could be enhanced under conditions of culture stress.