EXPRESSION OF SMALL REGIONS OF EQUINE HERPESVIRUS-1 GLYCOPROTEIN-C INESCHERICHIA-COLI

A series of truncated equine herpesvirus 1 (EHV1) glycoprotein C (gC) molecules was examined for use as serodiagnostic antigens for EHV1 and EHV4. Small regions of EHV1 glycoprotein C, an immunodominant EHV 1 g lycoprotein, were expressed in Escherichia coli as glutathione S-trans ferase (GST) fusion proteins using the bacterial expression vector pGE X-2T. Sera obtained from horses, including sera from specific-pathogen -free (SPF) foals, following exposure to either EHV1, EHV4 or both vir uses were used. Several of the fusion proteins were shown to encompass EHV1 specific epitopes while others encompassed strong, cross-reactiv e epitopes. One clone, termed pEC-3, produced a soluble and stable fus ion protein which encompassed amino acids 107-275 of EHV1 gC. Strong c ross-reactive epitopes on pEC-3 were localised to a region encompassed by amino acids 137 to approximately 152 while EHV1 specific epitope(s ) were identified downstream of this region, i.e., approximately amino acids 152 to 275. E. coli expressed EHV1 gC polypeptides showed clear potential for use as diagnostic reagents for the detection of cross-r eactive and type-specific EHV1 and EHV4 antibodies present in convales cent equine sera.