Studies on glycoprotein 13 (gp13) of equid herpesvirus 1 using affinity-purified gp13, glycoprotein-specific monoclonal antibodies and synthetic peptides in a hamster model

1 AFRC Institute for Animal Health, Pirbright Laboratory, Woking, Surrey GU24 0NF, 2 Department of Microbiology, The University of Leeds, Leeds LS2 9JT, 3 Department of Veterinary Pathology, University of Glasgow Veterinary School, Bearsden Road, Bearsden, Glasgow G61 1QH, U.K. and 4 Department of Veterinary Science, University of Kentucky, Lexington, Kentucky 40546-0076, U.S.A. Hamsters were immunized with either an affinity-purified preparation of equid herpesvirus 1 (EHV-1) glycoprotein 13 (gp13) or synthetic peptides representing three sequences within the homologous glycoprotein of EHV-4, resulting in the production of anti-peptide (in the case of peptide-immunized animals) or antivirus antibodies. The sera from gp13-immunized hamsters contained antibodies which showed virus-neutralizing activity and complement-mediated antibody lysis of EHV-1-infected target cells. These hamsters were protected from EHV-1 challenge. The characteristics of a panel of anti-gp13 monoclonal antibodies (P28, P17, 14H7, 16E4 and 16H9) were assessed both in vivo and in vitro . 16E4 and P28 showed high levels of complement-mediated neutralization of virus, complement-mediated lysis of virus-infected target cells and passive protection of hamsters. Furthermore, epitope mapping studies demonstrated that this glycoprotein contains a neutralizing epitope recognized by EHV-1-immune horse serum. The data imply that gp13 has potential as a candidate antigen for a molecular vaccine. Present address: National Institutes of Health, NIAID, Building 7, Room 106, Bethesda, Maryland 20892, U.S.A. Received 21 May 1990; accepted 14 January 1991.