Blastogenesis of human lymphocytes by endotoxin.

Lipopolysaccharides of S. typhimurium, S. enteritidis and E. coli at wide range of concentrations were used to induce blastogenesis in human and mouse (nude) lymphocytes. Human lymphocytes from peripheral blood showed positive response to at least one source of LPS (stimulation index of 2-9). The optimum concentration resulting in maximum stimulation varied with different individual, sources and concentrations of LPS used. Lymphocytes from cord blood failed to respond to LPS, but had positive response to PHA. All three LPS produced about equally strong mitogenic effects on mouse spleen cells.