Presence of antibody to human herpesvirus 6 in monkeys

A serological survey of monkeys was conducted to determine the prevalence of antibody to human herpesvirus 6 (HHV-6). Two-hundred and fifteen sera from 10 species of monkeys were examined by an immunofluorescent antibody (IF) assay. The antibody was found in monkeys from eight of the 10 species examined, but was not detected in silvered lutongs or cotton-top tamarins. The prevalence of antibody was highest in squirrel monkeys. Sera with high antibody titres were examined further by Western blot analysis and the neutralizing antibody test and the antibody levels were compared with that from a patient with exanthem subitum. On Western blotting, monkey and human sera that were antibody-positive to HHV-6 antigen gave similar reactions with antigen components of almost the same Mr. Furthermore, sera that were antibody-positive by the IF test were also positive by the neutralizing antibody test and their titres in the two tests were comparable. These results suggest the existence of HHV-6 or an HHV-6-related virus in monkeys.