Cell-mediated immunity and delayed-type hypersensitivity inPseudomonas aeruginosa-infected mice

Abstract

In mice repeated systemic injections of Pseudomonas aeruginosa viable cells were able to induce a specific delayed-type hypersensitivity, which was evaluated as increase both in footpad swelling and in the weight of popliteal lymph nodes, after a challenge in the footpad. Unfractionated spleen cells or T lymphocyte-enriched spleen cells from sensitized donors were able to specifically transfer the delayed-type hypersensitivity to syngeneic recipients but failed to protect them against a lethal challenge with P. aeruginosa. In contrast, serum or B lymphocyte and macrophage-enriched spleen cells from the same donors were capable of transferring protective immunity but failed to induce any delayed-type hypersensitivity reaction in the recipients. These results clearly show that in systemic P. aeruginosa infections a dissociation between delayed-type hypersensitivity and acquired cellular resistance occurs.

Mapping of the T-cell recognition sites of Pseudomonas aeruginosa PAK polar pili

“…This hyporesponsiveness is both acquired and specific and may play an important role in the irreversibility and destructiveness of the Pseudomonas infection (27). Later, Garzelli et al (8) and Campa et al (4) reported that mice with repeated systemic infections caused by P. aeruginosa can induce a specific delayed-type hypersensitivity after a challenge in the footpad. Furthermore, T-lymphocyte-enriched spleen cells from sensitized donors can specifically transfer this delayed-type hypersensitivity to syngeneic recipients.…”