Cytomegalovirus-induced immune suppression. I. Humoral immunity.

Murinecytomegalovirus (CMV) infects cells of the lymphoreticular system and causes alteration in immune function. Four to 6 days after infection, histological changes are observed in the spleen, consisting of intranuclear inclusions around germinal centres and destruction of germinal centres at higher virus inocula. Gradual healing takes place after this period. CMV also causes suppression of immune function, the maximal suppression also occurring in the 1st week after infection. Both the primary and secondary immune responses to sheep red blood cells are suppressed. The degree of immune suppression is directly related to virus inocula. When mice are first vaccinated with attenuated CMV, infection with virulent CMV results in an immune response greater than that observed in control mice.