Studies on the Influence of the Immunosuppressive Therapy to the Cytomegalovirus Infection. II. Experimental Studies on Cytomegalovirus Infection in Mice in the Immunosuppressive State

In succession to the previous studies on cytomegalovirus (CMV) infection in the clinical subjects, the experimental studies on mouse CMV (MCMV) infection were carried out using mice given immunosuppressive treatment. A group of mice were given 3 doses (200 mg/kg/dose) of cyclophosphamide after intraperitoneal inoculation of MCMV. Another group of mice were thymectomized within 24 hours after birth and infected with MCMV in adult age. The infected mice not given immunosuppressive treatment and non-infected mice given immunosuppressive treatment also studied as control groups. All groups of mice were examined for virus isolation, serum complement-fixing (CF) antibody and inclusion-bearing cells in various organs. The following results were obtained: 1) The generalization of MCMV infection was demonstrated only in the groups of mice treated with cyclophosphamide or thymectomy. Some of the mice took fatal course due to generalized infection. 2) Severe lymphocytic depletion was seen within the follicle and around the central arterioles in lymphoid organs of the mice given immunosuppressive treatment. 3) Development of CF antibody was also found to be suppressed in the mice treated with cyclophosphomide. The results of the clinical and experimental studies suggest that the immunosuppressive therapy induce reactivation of latent CMV infection, and that CMV would be disseminated and cause generalized disease leading to death, if patients were given powerful immunosuppressive therapy which could impair humoral and cellular immune mechanism