The mechanism of cholera toxin-induced suppression of natural killer cytotoxicity.

In a previous publication, it was reported that the pretreatment of mouse spleen cells with cholera toxin (CT) greatly inhibited their natural killer (NK) cytotoxicity. In the present study, it was found that ganglioside GM1 blocked the inhibitory effect of CT, and mature T cells and nylon-wool-adherent cells were not involved in the CT-mediated inhibition of NK cytotoxicity. It was also demonstrated that subunit A or B dissociated from CT lacked the capacity to inhibit NK cytotoxicity. In addition, CT-mediated inhibition was persistent and irreversible. The implications of CT-mediated inhibition of NK cytotoxicity are discussed.