PROTECTION AGAINST EHV-1 CHALLENGE INFECTION IN THE MURINE MODEL AFTER VACCINATION WITH VARIOUS FORMULATIONS OF RECOMBINANT GLYCOPROTEIN GP14 (GB)

Four formulations of the equine herpesvirus type 1 (EHV-1) glycoprotei n gp14 (gB), were tested for their ability to protect mice against int ranasal (inas) EHV-1 challenge infection. The preparations tested incl uded (i) a truncated gp14 produced in Escherichia coli or (ii) a trunc ated gp14 expressed in insect cells by a recombinant baculovirus, (iii ) truncated gp14 coexpressed with human immunodeficiency virus type 1 (HIV-1) gag virus-like particles (VLP) in insect cells, and (iv) a gp1 4-DNA vaccine under the control of the cytomegalovirus immediate early promoter. All antigen preparations and the DNA vaccine elicited a hum oral and delayed-type hypersensitivity (DTH) immune response to EHV-1 after intramuscular (im) immunization. After inas immunization, only t he VLP-gp14 preparation produced both a good humoral and a prominent D TH immune response; gp14 expressed by insect cells elicited high titer s of EHV-1-specific antibodies, whereas gp14 produced in E. coli and t he DNA vaccine elicited only low antibody titers. Glycoprotein gp14 ex pressed by bacteria, however, induced a strong DTH reaction after inas application. Mice were completely protected against EHV-1 challenge i nfection after both the im and the inas immunization with the VLP-gp14 preparation. Protection was less efficient after immunization with th e E. coil and insect cell gp14s as well as after DNA vaccination. Alth ough the transmembrane domain of EHV-1 gp14 was deleted, recombinant g p14 could be demonstrated in insect cell membranes at late times posti nfection and aggregated with the VLPs. It is suggested that the transm embrane domain is not required for gp14-association with membranes in that system. (C) 1995 Academic Press, Inc.