Mechanism of augmentation of antibody response in vitro by 2-mercaptoethanol

Abstract

The mechanism of augmentation of antibody response in vitro by 2-mer captoethanol (2 ME) was investigated. By employing cystine-free RPMI-1640 medium, it was demonstrated that cystine was absolutely required for eliciting the in vitro antibody response in murine lymphocytes. The augmentation by 2 ME was corn pletely dependent on the presence of cystine. Maximal response was reached when cysteine or cystine (as half cystine) was added at 2.5 mM where 2ME did not further enhanced the response. The serial feeding of cysteine, but not of cystine, amplified its potentiating activity at lower concentrations (≤1 mM) . The addition of 10-5M 2 ME to the medium shifted the dose-response curve to lower concentrations by about one order of magnitude. It was found that 35S-cystine was incorporated into lymphocytes one fifth more slowly than 35S-cysteine. Cystine uptake was accelerated by about 2.5-fold in the presence of 10-5M 2 ME. A close correlation was observed between doseresponse profiles of 2 ME in augmenting the antibody response and the stimulation of cystine uptake. These data suggest that one of the roles of 2 ME in augmenting antibody response in vitro is to facilitate the uptake of cystine which is contained in RPMI-1640 medium and which is utilized less efficiently than cysteine.