STIMULATION OF B-LYMPHOCYTES BY LIPOPOLYSACCHARIDES FROM ANAEROBIC-BACTERIA

Lipopolysaccharides (LPSs) from anaerobic gram-negative bacteria, incl uding those of low endotoxic activity that are isolated from Bacteroid es, Prevotella, and Porphyromonas are potent inducers of DNA replicati on and polyclonal immunoglobulin production in murine B lymphocytes. T he activation is dose-dependent and T cell-independent. Replication of DNA and production of immunoglobulins were also stimulated by lipid A and by the LPS heteropolysaccharide that were isolated by mild acid h ydrolysis of the LPSs of Bacteroides fragilis and Fusobacterium nuclea tum. Combinations of LPS, lipid A, and acid-degraded polysaccharide am plified the blastogenic response. Antibodies that react with the polys accharide part of LPSs isolated from members of the Bacteroidaceae are present in healthy human serum.