Out of 91 animals in 37 cages at the NEPRC, 5 cages contained all sVCA-seropositive animals, 7 cages contained all seronegative animals, and 25 cages contained both seropositive and seronegative animals

Out of 91 animals in 37 cages at the NEPRC, 5 cages contained all sVCA-seropositive animals, 7 cages contained all seronegative animals, and 25 cages contained both seropositive and seronegative animals. antigen (VCA) and EBNA-1, are widely used to document Epstein-Barr virus (EBV) infection (8, 13). Old World (4), and more recently New World (2), nonhuman primates are known to be naturally infected with related herpesviruses in the same lymphocryptovirus (LCV) genus as EBV. LCV infection in Old World primates was initially recognized by the presence of serum antibodies cross-reactive with viral antigens in EBV-infected B cells (7). As with humans, LCV seropositivity in Old World primates is highly prevalent both in nature and in domesticated colonies, with seropositivity in more than 95% of adult animals (5, 7, 9). The biology of LCV infection in IQ-1S Old World primates appears to be nearly identical to that of EBV infection in humans (16). This is concordant with the identical repertoire of viral genes and the high degree of sequence homology between EBV and rhesus LCV, a prototype for an Old World LCV whose genome has recently been fully sequenced (11). It was long believed that LCV did not infect New World primates, since there was no strong evidence of EBV cross-reactive antibodies from these species. However, we recently isolated a B-cell-immortalizing herpesvirus from a spontaneous B-cell lymphoma arising in a common marmoset (= 165 and 126, respectively). The results support the findings that LCV infection may not be as ubiquitous among marmosets as it is among humans and Old World primates. Common marmosets are typically housed in smaller units than Old World primates, so a lower prevalence of marmoset LCV infection could be due to segregation of seropositive and seronegative animals IQ-1S in domesticated colonies. Therefore, we examined the housing patterns of animals in relation to seropositivity. Out of 91 animals in 37 cages at the NEPRC, 5 cages contained all sVCA-seropositive animals, 7 cages contained all seronegative animals, and 25 cages contained both seropositive and seronegative animals. Thirty of forty-three seropositive animals were housed in cages with both seropositive and seronegative animals. Similarly, 29 out of 48 seronegative animals were housed in cages with both seropositive and seronegative animals. Thus, a significant portion of seronegative animals (19 of 48; 40%) were segregated with other naive animals, suggesting that housing practices may contribute to a lower seroprevalence of marmoset LCV infection. However, the large percentage of IQ-1S mixed cages and large number of seronegative animals in mixed cages (60%) also suggest that LCV infection may not be readily transmitted among marmosets. In contrast, virtually all newborn Old World primates, Mouse monoclonal to KSHV ORF26 such as rhesus macaques and baboons, turn seropositive within 1 year when housed with other seropositive animals (5, 9). In order to eliminate potential bias from domestic housing, sera collected from common marmosets shortly after capture from the wild were also tested. Twelve out of 24 animals (50%) tested positive by the sVCA EIA, indicating reduced seroprevalence among New World primates in the wild, similar to animals in domestic colonies. These are the first serologic studies of LCV infection in New World primates. Historically, the failure to reliably detect EBV cross-reactive antibodies in New World primates was probably due to the degree of sequence divergence between EBV and marmoset LCV genes, exacerbated by additional divergence between human and marmoset immunoglobulins. Thus, important technical aspects in these studies were the use of antigens IQ-1S derived from marmoset LCV sequences and anti-human immunoglobulin secondary reagents that had not been absorbed for reactivity to immunoglobulins from other mammalian species. The combined use of lytic and latent antigens that are immunodominant in EBV and rhesus LCV infection identified largely identical positive and negative populations among NEPRC animals..