ROLE OF GAMMA-DELTA T-CELLS IN MURINE CHLAMYDIA-TRACHOMATIS INFECTION

The role of gamma-delta T cells in host resistance to Chlamydia tracho matis was characterized by using a murine model of pneumonia caused by the mouse pneumonitis agent (MoPn), murine C. trachomatis. At days 3 and 7 after infection, gamma-delta T-cell-deficient knockout mice had significantly higher levels of MoPn in the lungs than did immunologica lly intact controls. At day 20, paradoxically, gamma-delta T cell-defi cient mice were more resistant to MoPn than were controls. This increa sed resistance was not due to an increased production of toxic cytokin es or interleukin-10 in controls on that day. Gamma-delta T cells play a role in protection early in MoPn infection, but they may be deleter ious later in infection, as has been observed in models of salmonella and trypanosome infection.