Generation of antibody-mediated regulation during in vitro clonal expansion of memory B lymphocytes

While examining the in vitro antigen-mediated expansion of the dinitrophenyl- (DNP) reactive memory B cell pool, the authors have noted the development of 2 regulatory mechanisms. In these studies they used an in vitro system involving 2 sequential antigen challenges (day 0 and day 11) and an extended culture period. They observed the development of hapten-augmentable plaque-forming cells (PFC). The appearance of hapten-augmentable PFC was associated with the presence in the culture supernatants of an inhibitor of antibody secretion. Data on hapten-augmentable plaques suggest that this inhibition of antibody secretion is occurring by the interaction of an antigen-antibody complex with surface immunoglobulin. Present data indicate that this feedback inhibition acts solely at the effector phase without affecting the differentiation of precursors to antibody-forming cells. Even though hapten-augmentable PFC have been reported as indicative of anti-idiotypic regulation, they have found no evidence for regulation either by anti-idiotypic antibody or idiotype-specific suppressor cells.