Stimulation of human peripheral blood lymphocytes by lipopolysaccharide (LPS) was studied by the incorporation of 3H-thymidine. Peak stimulation occurred at 7 to 9 days over a broad range of LPS concentrations. Both Escherichia coli and Salmonella typhimurium LPS were effective mitogens with S. typhimurium having slightly higher activity. There was a strict serum requirement; pooled fresh frozen human serum was found to best support stimulation. In fetal calf serum, LPS caused a reduction in culture-induced stimulation. Cell separation procedures were employed in order to study the nature of the responding cell population. It was found that only non-T cells were stimulated by LPS, but in order for maximal stimulation to occur there was a requirement for helper T cells.

1

Supported by Research Contract (NO1-CP-43228 from the National Cancer Institute, National Institutes of Health, DHEW, and by gifts to the Joseph Edward Luetje Memorial Fund for Lymphoma Research.

This content is only available via PDF.