A hamster model of equine herpesvirus type 1 (EHV-1) infection; passive protection by monoclonal antibodies to EHV-1 glycoproteins 13, 14 and 17/18.

Following intraperitoneal or intranasal inoculation of the Syrian hamster with equine herpesvirus type 1 (EHV-1), strain Kentucky D, virus replicated in the liver and lungs reaching a peak at 4 days post-infection (p.i.). By day 6 p.i. virus titres in these organs had reduced and the spleen contained virus-specific cytotoxic cells. This cytotoxicity was mediated by T cells since treatment of effector cells with a monoclonal antibody to hamster T lymphocytes inhibited the effect. An antiviral humoral immune response was present by day 4 when antibodies capable of lysing EHV-1-infected target cells in the presence of complement were detected. The transfer of serum from recovered hamsters into naive recipients 24 h before challenge prevented virus infection, whereas serum transferred 24 h after challenge reduced the titre of virus recovered from target organs. Inoculation of hamsters with monoclonal antibodies directed to glycoproteins 13, 14 and 17/18 of a subtype 1 virus (Army 183) before virus challenge protected hamsters. This hamster model will prove useful for studying the immune response to EHV-1 and evaluating the immunogenicity of individual virus components.