Immunoglobulins in Human Serum Reactive with Murine Friend Leukaemia Virus

Abstract

Fresh human sera neutralize Friend leukemia virus (FLV). The activity is abolished by heating (56.degree. C for 30 min), hydrazine and EDTA treatment, suggesting the involvement of complement. Human sera also contain antibody which specifically reacts with FLV. Following incubation with human whole serum, Ig[immunoglobulin]G and F(ab'')2 fragments, FLV acquires the ability to bind anti-human Ig sera as shown in neutralization and radioimmunoprecipitation assays. The same is true for FLV-infected [mouse spleen and erythroleukemia] cells but not for uninfected controls cells, as assessed by immunofluorescence. The binding of antibody to FLV-infected cells is prevented by pre-treating the cells with antisera to FLV and FLV-gp71, and is competed by FLV, FLV-gp71 and, to a lesser extent, by FLV-p12 and p30.