Impairment of cell-mediated immunity in Pseudomonas aeruginosa pyelonephritis: lack of suppressor cell activity in vivo.

Bacterial pyelonephritis was induced in mice by direct microinoculation of Pseudomonas aeruginosa in the kidney. In the acute phase of P. aeruginosa pyelonephritis, a state of cell-mediated immunity impairment, evaluated both in vitro as lymphocyte reactivity to concanavalin A and in vivo as host versus graft reaction has been observed. Furthermore, delayed-type hypersensitivity to specific bacterial antigen has been detected only when the kidney infection was subsiding, i.e., 3 weeks after bacteria inoculation. When investigating the mechanism of such T-cell impairment, we were unable to transfer the immunodepression, suggesting that suppressor cells are not involved in vivo. The role of P. aeruginosa inhibition of cell-mediated immunity in the pyelonephritic host is discussed.