The Immunosuppressive Effects of Rauscher Leukemia Virus Upon Spleen Cells Cultured in Cell-Impermeable Diffusion Chambers

Abstract

Abstract Qualitative and quantitative differences were demonstrated in the effects of Rauscher leukemia virus (RLV) upon various expressions of the immune response. BALB/c mouse spleen cells were inoculated with RLV and cultured in cell-impermeable diffusion chambers. The suppressive effects of RLV on the cellular expression of IgM and IgG memory and on the cell responses to phytohemagglutinin (PHA) and alloantigens were investigated. RLV inoculated at time zero of culture inhibited IgG but not IgM memory. Both responses were depressed when the interval between RLV inoculation and antigenic restimulation was increased. Removal of the macrophage-rich, adherent cell population depressed the IgM but not the IgG response, indicating that the early selective inhibition of IgG memory was not dependent on infection of macrophages by RLV. Incorporation of 3H-TdR was higher in cultures of spleen cells infected with RLV than in non-infected controls. This high background precluded accurate measurement of stimulation of DNA synthesis by RLV-infected BALB/c cells cultured with mitomycin-treated C57BL mouse spleen cells. However, infected cultures responded to PHA stimulation with 3H-TdR incorporation similar to that of the non-infected, PHA-stimulated cells. These data indicated that RLV-induced immunosuppression is not an all-or-none phenomenon; the degree of inhibition appeared to depend on the different immunocompetent units participating in various immune responses.