VIRAL ABROGATION OF LYMPHOCYTE MITOGENESIS - INDUCTION OF A SOLUBLE FACTOR INHIBITORY TO CELLULAR PROLIFERATION

Abstract

PHA [phytohemagglutinin] and Con [concanavalin] A driven mitogenesis of C3H mouse lymphocytes can be inhibited by co-incubation with a variety of different virus particles [e.g., avian Rous sarcoma virus, avian myeloblastosis virus, Sendai virus and vesicular stomatitis virus]. These effects appear independent of infection, and can be obtained using UV-inactivated virus. Viruses may be added to spleen cell cultures as late as 46 h after co-incubation with mitogen, and still achieve significant inhibition of proliferative responsiveness. The described inhibition is apparently mediated, in part at least, by a soluble factor which is induced in splenic cultures following interaction with virus particles. This factor is apparently a product of macrophages. It does not possess interferon activity, but does have the ability to inhibit lectin- and alloantigen-driven mitogenesis, as measured in fresh cultures of splenic lymphocytes and in the mixed lymphocyte culture (MLC) reaction, respectively. Addition of virus to splenic cultures can apparently activate suppressor lymphocytes with the ability to inhibit proliferative responsiveness of fresh lymphocyte suspensions in the presence of Con A.