Evidence for autoantibody production associated with polyclonal B-cell activation by Pseudomonas aeruginosa

Experimental infection of mice with Pseudomonas aeruginosa resulted in the polyclonal activation of B lymphocytes, as assessed by the spontaneous plaque-forming cell (PFC) response to trinitrophenyl and sheep erythrocytes. Additionally, a PFC response to bromelain-treated syngeneic erythrocytes (Br-MRBC) could be detected in infected mice, suggesting that P. aeruginosa infection might also induce activation of self-reactive B-cell clones and consequently lead to autoantibody production. Furthermore, in cultures of mouse peritoneal cells, heat-killed P. aeruginosa enhanced the development of anti-Br-MRBC PFC, even under conditions where cell division was blocked, suggesting that the in vitro P. aeruginosa-induced enhancement of anti-Br-MRBC PFC was essentially related to cell differentiation, cell division playing only a minor role. The mechanism of the in vivo and in vitro P. aeruginosa-induced activation of anti-Br-MRBC PFC are discussed.