Augmentation of in vitro antibody response by disulfide compounds. I. Comparison between intermolecular and intramolecular disulfides.

The following disulfide compounds: 2-hydroxyethyldisulfide (2-MEox), 2-aminoethyldisulfide (cystamine) and oxidized dithiothreitol (DTTox) were found to augment the in vitro antibody response to sheep erythrocytes in murine lymphocytes as effectively as their reduced forms when they were added to the culture medium. We, however, found out that the mode of action of DTTox was greatly different from that of 2-MEox or cystamine. 2-MEox and cystamine showed augmenting effects on the proliferative response to lipopolysaccharide and on the uptake of (35S)-cystine by the lymphocytes. In contrast to these intermolecular disulfides, DTTox, an intramolecular disulfide compound, was found to be inactive in these systems. 2-MEox and cystamine, but not DTTox, were reduced to thiol forms by the intact lymphocytes or by the cell homogenate. Thus, it is likely that DTTox did not behave as the reduced form in the lymphocyte culture in contrast to 2-MEox and cystamine, suggesting that the disulfide form itself plays an important role in augmenting effects of DTTox.