Glycoprotein C of bovine herpesvirus 5 (BHV-5) confers a distinct heparin-binding phenotype to BHV-1

Bovine herpesvirus type 1 (BHV-1) causes respiratory and genital diseases i n cattle, whereas the closely related BHV-5 can induce severe meningoenceph alitis in calves. To characterize BHV-5 glycoprotein C (gC5) within the bac kbone of BHV-1, three consecutive recombinant viruses were constructed: A d eletion mutant (rBHV-1 Delta gC blue) with gC1 replaced by the lacZ gene, a n exchange mutant (rBHV-1gC5) with the lacZ of BHV-1 Delta gC blue exchange d by gC5, and a rescue mutant (rescue BHV-1) from rBHV-1gC5 with an additio nal XbaI site in gC1. The recombinant and wildtype viruses were characteriz ed on MDBK cells. Although no significant differences were observed in grow th behaviour and entry kinetics, rBHV-1gC5 showed a distinct phenotype in a heparin blocking assay. The gC5 was able to transfer the heparin binding p henotype of BHV-5 to BHV-1. This indicates that gC1 and gC5 differ in their receptor binding qualities, which might modulate the ability of the viruse s to spread within the central nervous system.