The effect of Isoprinosine treatment on persistent infection of Balb/c mice infected with murine gammaherpesvirus 68

: We demonstrated the positive effect of Isoprinosine treatment on persistent infection of Balb/c mice with murine gammaherpesvirus 68 (MHV-68). Increased number of leukocytes, increased percentage of neutrophils, elevated levels of virus-neutralizing (VN) antibodies, reduced number of atypical lymphocytes and reduced virus titers were detected in the examined organs after a 14-day treatment. The positive effect of Isoprinosine therapy vanished after 120-150 days. After this interval, we demonstrated lower numbers of leukocytes, lower levels of VN antibodies and an increased number of atypical lymphoid monocytes in the Isoprinosine-treated group. Immunological parameters correlated with increased titers of virus in all investigated organs. Evidence of immunostimulation was demonstrated by lower incidence of tumor formation (7.5%) in the group of MHV-infected and Isoprinosine-treated mice in comparison to group without Isoprinosine treatment (17.5%). The presented results showed that Isoprinosine therapy had a positive impact on persistent infection of mice with MHV-68, but this effect was time-limited. The improvement of the investigated parameters lasted for five months only. Our presented results confirmed that each treatment with Isoprinosine should be repeated and must be long-term in some chronic infections.