ADAPTATION OF EQUINE HERPESVIRUS-1 TO UNNATURAL HOST LED TO MUTATION OF THE GC RESULTING IN INCREASED SUSCEPTIBILITY OF THE VIRUS TO HEPARIN

Heparin extensively inhibited infection of MDBK cells by equine herpes virus 1 (EHV-1) strains adapted to bovine cells or hamsters, while the reagent merely reduced infectivity of strains passaged only in equine cells. The gC of two strains adapted to non-equine cells seemed to ha ve higher affinity for heparin, although the reagent bound to both the gC and gB of all strains tested. Amino acid substitutions of the gC o f the EHV-1 strains adapted to non-equine cells converged on the hydro philic regions, amino acid residues 92 to 175, resulting in the glycop rotein becoming more cationic. These results indicate that these hydro philic regions of the gC may be responsible for binding to heparin.