Several SA8 isolates obtained from baboons were compared to the protot
ype SA8 herpesvirus of African green monkeys. SDS-PAGE and restriction
enzyme analyses revealed definite differences between green monkey an
d baboon isolates. DNA and amino acid sequences of the gB, gD and gJ g
lycoprotein genes exhibited substantial differences in variable region
s. For the gB and gD, the amount of amino acid substitutions between S
A8 and the baboon viruses was comparable to levels observed between an
alogous genes of SA8 and B virus or HSV1 & HSV2. Although a high degre
e of antigenic crossreactivity was apparent, virus-specific antigenic
determinants were also readily detected. Phylogenetic analyses support
ed separation of the baboon isolates and SA8 as distinct viruses. Take
n together these results suggest that although closely related to SA8,
the baboon viruses represent a distinct simian alpha-herpesvirus whic
h we propose be designated Herpesvirus papio 2.