Deregulation of mouse antibody-forming cells by streptococcal pyrogenic exotoxin (SPE)

Induction of murine cytolytic T lymphocytes by Pseudomonas aeruginosa exotoxin A

“…Lately, a number of microbial products, including exotoxins, have been shown to possess mitogenic activities through which they alter immune responsiveness (4,10,12,14,17,19). Results presented in this study clearly show that PA at subcytotoxic concentrations is a T-cell mitogen as well as a T-cell-dependent B-cell mitogen.…”

“…The model for these experiments consisted of splenocytes from BALB/c mice primed 95 days earlier with EL4 and induced in vitro for 1 to 10 days with optimal concentrations of PA or ConA; the activity of the splenocytes was assessed against the original priming target cells (EL4 Staphylococcal enterotoxins as well as pyrogenic toxins produced by the same bacteria and by Streptococcus pyogenes have been shown to be highly potent T-cell mitogens (4,5,13,19,24,25). As are many other plant mitogens, these toxins are capable of inducing suppressor and helper activity, as well as cytolytic activity, in the immune system (4,6,7,13,19,25,28). Other bacterial protein toxins, like cholera toxin and PA, also enhance or suppress the immune response (8,9,14,17,22).…”

“…A preliminary report by Pavlovskis et al 22and two recent studies by Holt and Misfeldt (8,9) have shown that PA has a modulatory effect on the humoral immune response, mediated through its ability to induce changes in the composition of the lymphocyte population. Many exotoxins produced by various bacterial species have also been shown to exert a modulatory effect on the immune response (4,6,7,13,14,17,19,25,29).…”