Anti-lipid A monoclonal antibodies and anti-LPS antiserum effects on limulus activity of LPS.

Anti-lipid A monoclonal antibodies (A78S1 and A523) and anti-LPS antiserum can decrease the mortality due to endotoxic shock in the newborn rat. However, in vitro LPS detoxification of anti-lipid A monoclonal antibodies is not known. Thus, we studied in vivo effects of A78S1 (IgG), A523 (IgM), and anti-LPS antiserum on Limulus activity. Anti-LPS antiserum decreased Limulus activity of S. enteritidis, E. coli and S. typhosa LPS. However, neither A78S1 nor A523 decreased the Limulus activity of E. coli and S. typhosa LPS. A78S1 or A523 incubation with S. enteritidis LPS at different doses (0.1 to 100 ng/ml) did not alter the Limulus activity. Perchloric acid treatment after LPS incubation with A78S1 or A523 significantly decreased Limulus activity. Therefore, antilipid A monoclonal antibodies (A78S1 and A523) can bind LPS, but do not decrease Limulus activity.