IDENTIFICATION AND CHARACTERIZATION OF A BOVINE HERPESVIRUS-1 (BHV-1)GLYCOPROTEIN GL WHICH IS REQUIRED FOR PROPER ANTIGENICITY, PROCESSING, AND TRANSPORT OF BHV-1 GLYCOPROTEIN GH

DNA sequence analysis of the bovine herpesvirus-l (BHV-1) genome revea led the presence of an open reading frame named UL1 which exhibited li mited homology to glycoprotein gL of herpes simplex virus-1 (S. K. Kha ttar, S. van Drunen Littel-van den Hurk, L. A. Babiuk, and S. K. Tikoo , Virology 213, 28-37). To identify the BHV-1 UL1 protein, rabbit anti sera were prepared against two synthetic peptides that were predicted by computer analysis to encompass antigenic epitopes Sera against both peptides immunoprecipitated a 16- to 17-kDa protein from in vitro tra nslated in vitro transcribed mRNA, BHV-1-infected MDBK cells, and puri fied virions. Enzymatic deglycosylation and lectin binding assays conf irmed that the BHV-1 UL1 protein contains only O-linked oligosaccharid es and was named glycoprotein gL. Sera against UL22 protein immunoprec ipitated a protein of 108 kDa from BHV-1-infected MDBK cells and purif ied virions, which was modified only by N-linked oligosaccharides and was named glycoprotein gH. Glycoprotein gL expressed by recombinant va ccinia virus was properly processed and secreted into the medium. In c ontrast glycoprotein gH expressed by recombinant vaccinia virus was fo und to be retained in the rough endoplasmic reticulum. However, gH coe xpressed with gL by recombinant vaccinia viruses was properly processe d and transported to the cell surface, suggesting that complex formati on between gH and gL is necessary for the proper processing and transp ort of gH but not gL. In addition gH-gL complex formation is also requ ired for induction of neutralizing antibody response and anchoring of gL to the plasma membrane. (C) 1996 Academic Press, Inc.