Lymphocyte Reactivity Contributes to Protection Conferred by Specific Antibody Passively Transferred to Herpes Simplex Virus-Infected Mice

Abstract

Passively acquired immunity to herpes simplex virus (HSV) was studied in antithymocyte serum (ATS)-treated mice and athymic nude mice to determine whether immunocompetent lymphocytes contribute to the protection observed after transfer of HSV-specific antibody to infected animals. Mice were given 3 i.p. injections of 0.1 ml of ATS at 24 h intervals. This treatment reduced concanavalin A and lipopolysaccharide stimulation of lymphocytes harvested from these animals by 90% when compared with the stimulation of lymphocytes harvested from untreated animals. I.p. injection of 0.5 ml of specific antibody 8 h after corneal HSV type 1 infection or s.c. HSV type 2 infection did not protect ATS-treated animals from virus infection. Specific antibody passively transferred to ATS-treated animals 8 and 120 h postinfection also failed to protect lymphocyte-depleted animals from HSV. ATS-treated animals were protected from HSV infection by passively acquired antibody when lymphocytes harvested from these animals regained 80% of their ability to be stimulated with concanavalin A and lipopolysaccharide. Specific antibody conferred protection to nude mice infected with HSV only if they were first reconstituted with syngeneic thymus cells 48 h before infection. Antiviral antibody and thymus-derived lymphocytes apparently contribute to the recovery of HSV-infected hosts after passive immunization.