MURINE CYTOMEGALOVIRUS - ASSOCIATED PNEUMONITIS IN THE LUNGS FREE OF THE VIRUS

At 4 wk after intraperitoneal inoculation of murine cytomegalovirus (M CMV) in adult BALB/c mice, MCMV remained detectable only in the saliva ry glands. When T cells of these mice were activated by a single injec tion of anti-CD3 epsilon monoclonal antibody, mice died of interstitia l pneumonitis at 24-48 h after injection, accompanied by elevation of serum levels of TNF-alpha and IFN-gamma. However, MCMV remained undete ctable in the lungs during the period. Simultaneous injection of cyclo sporin A reduced such effects of anti-CD3. In conclusion, although the presence of MCMV in the host may be required, MCMV-associated pneumon itis is not mediated by virus in the lung but probably by the cytokine s released from T cells, of which responsiveness to stimulation via CD 3 molecule has been presumably modified by MCMV infection.