LYMPHOCYTIC CHORIOMENINGITIS VIRUS-INDUCED ALTERATIONS OF T-HELPER-MEDIATED RESPONSES IN MICE DEVELOPING AUTOIMMUNE HEMOLYTIC-ANEMIA DURINGTHE COURSE OF INFECTION

The effect of LCMV on CD4+ T lymphocytes was analyzed in C3HeB/FeJ mic e after infection with the Docile strain of this virus, Our results in dicated that LCMV triggers: i) an inhibition of Th2 lymphocyte differe ntiation induced by concomitant immunization with a nonviral protein a ntigen; ii) a depression of T helper-dependent antibody responses elic ited by such an immunization; and iii) a CD4+ cell-mediated proliferat ion of spleen cells leading to increased interleukin-4 and interferon- gamma message expression and lgG2a-restricted total immunoglobulin sec retion, Taken together, these results indicate that LCMV profoundly af fects CD4+ cell-mediated immune responses in infected animals. Such mo dulations of T-helper functions may explain the preponderance of lgG2a in the antierythrocyte autoimmune response induced by the virus in C3 HeB/FeJ mice.