Reactivation of Toxoplasma gondii infection often occurs concurrently with active cytomegalovirus (CMV) disease in immunocompromised patients, and CMV disease results in immunosuppression. To determine if murine CMV (MCMV) infection decreases resistance to T. gondii, mice with latent T. gondii infection were infected with MCMV. T. gondii infection reactivated, manifested primarily as pneumonia. Lung macrophages supported the growth of T. gondii before, during, and after T. gondii reactivation. Peritoneal macrophages inhibited the growth of T. gondii as pneumonia developed and became permissive as pneumonia resolved. Mice with latent T. gondii infection could survive larger doses ofMCMV than could controls. Thus, MCMV infection led to reactivation of latent T. gondii infection in mice. Activation of lung macrophages, assessed by their ability to inhibit replication of T.gondii in vitro, wasnot associated with control of T.gondii infection.
Bibliographical noteFunding Information:
Receivedfor publication 21 December 1988and in revised form 27 March 1989. This work was presented in part at the 27th Interscience Conference on Antimicrobial Agents and Chemotherapy, held 4-7 October 1987, in New York City. This work was supported in part by research funds from the Veterans Administration, funds from the Minnesota Medical Foundation, and grant AI-24186 from the National Institute of Allergy and Infectious Diseases. Dr. Pomeroy is an Associate Investigator in the Veterans Administration Career Development Program. The authors thank Jack S. Remington for advice and John E. Fischer and Kathleen M. Carroll for technical assistance. Please address requests for reprints to Dr. Claire Pomeroy, Minneapolis Veterans Administration Medical Center, (l51), One Veterans Drive, Minneapolis, MN 55417.