Mamchak, AHodgkin, Phillip D2015-12-130818-9641http://hdl.handle.net/1885/89322Over 20 years ago, Coutinho and Moller reported that high concentrations of LPS were paralytic for the development of antibody secreting cells (ASC). This data was used to explain bell-shaped dose-response curves observed for antihapten antibody formation in response to haptenated LPS. In turn, this bell curve was used to formulate the one-signal model of B cell activation, which argued that antigen signalling was generally unimportant to B cell responses. The present paper re-examines LPS dose-response curves and finds results that do not support the view that high doses of LPS inhibit B cell differentiation to ASC. If high-dose paralysis is not an attribute of LPS stimulation, then the bell-shaped dose curve for hapten-specific ASC originally observed by Coutinho and Moller required an alternative explanation. Through the use of haptenated Ficoll, it was possible to show that the generation of LPS-induced antitrinitrophenol ASC could be inhibited by antigen presented on an inert substrate. Thus, the transmission of surface Ig-mediated (antigen) signals at higher concentrations can explain the antihapten bell-shaped dose curves, in contradiction to the conclusions of the one-signal model.Keywords: hapten antibody; immunoglobulin G; lipopolysaccharide; lymphocyte membrane immunoglobulin; animal cell; antibody production; antibody response; article; B lymphocyte; B lymphocyte activation; B lymphocyte differentiation; controlled study; lymphocyte subp B lymphocyte; Lipopolysaccharide; Surface immunoglobulin-mediated (antigen) signal; T cell independent antigen200010.1046/j.1440-1711.2000.00895.x2015-12-12