Prevalence of Herpesvirus papio 2 in baboons and identification of immunogenic viral polypeptides

The prevalence of Herpesvirus papio 2 (HVP2) in several groups of captive and wild-caught baboons was determined by detection of anti-HVP2 antibodies in 133 sera of adult baboons. Over 90% of newly imported (wild-caught) adult olive baboons (Papio anubis) from Kenya and chacma baboons (P. ursinus) from South Africa were found to have anti-HVP2 titers. Similarly, approximately 85% of captive breeding colony baboons (P. anubis and P. cynocephalus) were seropositive for HVP2. Infected animals were generally easily identifiable by enzyme-linked immunosorbent assay because anti-HVP2 IgG titers in immune animals were usually high (16,000 to 64,000). There was little variation in the relative reactivity patterns of individual HVP2-immune sera when tested against herpes simplex viruses 1 and 2, monkey B virus, H. cercopithecus 2, and HVP2, or against different HVP2 strains. Also, differences were not detected between reactivity of olive and chacma baboon immune sera. Analysis of the polypeptide specificity of immune sera by western blot identified four viral antigens that were consistent targets of immune sera. These antigens were the gB glycoprotein, a pair of unidentified glycoproteins of 80 to 100 kDa, the gD glycoprotein, and a series of smaller capsid proteins. Additional viral proteins were variably recognized by individual immune sera. The results of this study indicate that HVP2 is a common infection of baboons; there is little antigenic variation among HVP2 strains; and there are several HVP2 antigens that represent consistent targets of the anti-HVP2 immune response of baboons.