Wild-Type Gross Leukemia Virus. I. Soluble Antigen (GSA) in the Plasma and Tissues of Infected Mice2

Abstract

A soluble antigen associated with Gross virus (G soluble antigen: GSA) is demonstrable in the plasma and tissue extracts of infected mice. It is serologically distinct from the soluble antigen previously demonstrated in the plasma of mice infected with Friend, Moloney, and Rauscher leukemia viruses. GSA is heat-labile and is not retained by 10 mμ filtration. It is found in the plasma and tissue extracts of all mice of strains with a high incidence of spontaneous leukemia (G+ strains) throughout their life and of mice inoculated with Passage A Gross virus. Detection of GSA in the blood provides a means to distinguish mice that have an exceptionally high risk of leukemia as a result of natural infection with Gross virus in the absence of an accompanying immune response. Probably GSA is a subunit of the virus coat with type-specific antigenicity, in contrast to the internal group-specific antigen demonstrable by immunoprecipitation.