In Vitro Study of Antiviral Activity of Immune Spleen Cells in Experimental Venezuelan Equine Encephalomyelitis Infection in Mice

Abstract

VEE-immune spleen cells from C57BL/6 mice exert a potent inhibitory effect on VEE viral growth in vitro when co-cultivated with infected L cell cultures. This inhibitory effect is both immunologically specific and dependent on time of spleen cell harvest after donor immunization with attenuated VEE virus. Neither interferon nor neutralizing antibody appear to be responsible for this specific antiviral activity. Studies with purified spleen or peritoneal cell populations demonstrate that only immune macrophages alone, or the combination of immune lymphocytes with normal macrophages, are active in inhibiting VEE-virus growth in cell culture. Finally, treatment of VEE-immune spleen cells with cytotoxic antisera directed at eliminating T cells removes the inhibitory effect on VEE replication in cell culture. Hence a two-cell system involving immunocompetent T cells and activated macrophages is proposed for the inhibition of VEE viral growth.