A subset of type-specific epitopes map in the amino terminus of herpes simplex virus type 1 glycoprotein B.

We constructed a recombinant herpes simplex virus (HSV) containing the transcribed coding and non-coding sequences of HSV-1 strain F glycoprotein B (gB) gene, a gamma 1 gene, fused to the promoter-regulatory sequences of the HSV-1 alpha 4 gene and inserted into the thymidine kinase gene of RH1G44, an HSV-1 x HSV-2 recombinant that contains an HSV-2 gB gene at the natural locus. Phenotypic analyses of the insertion mutant, R3145, showed that the alpha gB gene was transcribed in the presence of cycloheximide but underwent partial conversion to the HSV-2 form. Nucleotide sequencing of the gene indicated that the 5' crossover occurred between nucleotides 107 and 117 upstream from the translation initiation site and that the 3' crossover occurred between the sequences specifying amino acids 402 and 412 of the HSV-1 gB. The chimeric protein consisted of an N-terminal 405 to 415 amino acids encoded by the HSV-2 gene and a C-terminal 462 to 472 amino acids encoded by the HSV-1 gene. Comparison of the reactivity of the parental and recombinant gB with type-specific monoclonal antibodies indicated that the chimeric gB lost reactivity with four HSV-1-specific antibodies but gained reactivity with three HSV-2-specific antibodies.