Expression and characterisation of equine herpesvirus 1 glycoprotein H using a recombinant baculovirus.

A recombinant baculovirus capable of expressing the glycoprotein H (gH) gene of equine herpesvirus 1 (EHV-1) was constructed. EHV-1 gH gene products in recombinant baculovirus infected insect cells were identified as 105 kDa and 110 kDa species compared with a 115 kDa product detected in EHV-1 infected mammalian cells. The extent of N-glycosylation of EHV-1 gH in both insect and mammalian cells was indicated by a shift in apparent molecular weights after PNGase F treatment to 90 kDa and 95 kDa forms, which compared with the predicted value of 90 kDa for the unglycosylated polypeptide. The recombinant EHV-1 gH was recognised by equine sera demonstrating that EHV-1 gH is a target for the immune system of the natural host. However, while the recombinant EHV-1 gH product from infected insect cells was immunogenic in mice, it did not induce a neutralizing antibody response against EHV-1.