In vitro T cell-mediated killing of Pseudomonas aeruginosa. III. The role of suppressor T cells in nonresponder mice

T lymphocytes from immune BALB/c mice can adoptively transfer protection against infection with the extracellular Gram-negative bacterium Pseudomonas aeruginosa to nonimmune recipients, and in vitro, immune T cells are able to kill these bacteria. Earlier studies indicated that this killing is mediated by a bactericidal lymphokine. The current studies demonstrate that T cells from immunized CB.20 mice, a strain congenic with BALB/c, fail to kill Pseudomonas aeruginosa in vitro. This nonresponsiveness is attributable to the activity of suppressor T cells of the Lyt-1^-, 2,3⁺, I-J⁺ phenotype. CB.20 mice are known to differ from BALB/c mice only at a single locus, which includes the Igh-1 allotype C(H) genes. These results suggest a critical role for this locus or closely linked genes in the control of T cell killing of this extracellular bacterium.