Immunophenotyping of leukocytes in peripheral blood of BALB/c mice infected with mouse herpesvirus isolate 72

We characterized leukocytes in peripheral blood of BALB/c mice infected with mouse herpesvirus isolate 72 (MHV-72) representing an isolate of mouse herpesvirus strain 68 (MHV-68, species Murid herpesvirus 4, genus Rhadinovirus, subfamily Gammaherpesvirinae, family Herpesviridae) (van Regenmortel et al., 2000). In acute infection (up to day 30 post infection (p.i.)) the number of CD8+ T cells increased, reaching a maximum at day 11 p.i. This increase correlated with that of CD4+ T, activated CD 19+ B and natural killer (NK) cells. At day 30 p.i. the numbers of CD4+, CD8+, CD14+ and CD19+ cells decreased to normal values. A similar increase in the number of these cells was observed at day 730 p. i. In the course of persistent infection (after day 30 p.i.) some of the mice developed a leukemia-like syndrome characterized by an increase in the number of leukocytes and appearance of atypical, blastic immature forms of leukocytes. The latter forms of leukocytes were characteristic by an increased amount of argyrophilic proteins. These results show further similarities between MHV-72 (another isolate of MHV-68) and EBV infections and justify the use of MHV-68 or MHV-72 as an appropriate mouse model for the study of EBV infection of humans.