Bacterial lipopolysaccharide induced B cell activation is mediated via a phosphatidylinositol 3-kinase dependent signaling pathway.
Bacterial lipopolysaccharide (LPS) is a potent stimulant of B cells and macrophages. LPS induces B cell proliferation and differentiation into antibody secreting cells. In addition, LPS also stimulates IL-6 secretion in mature B cells and in immature B cell lines such as WEHI-231. Although sufficient literature is available on LPS induced signaling events in monocytes and macrophages, the mechanisms involved in LPS induced B cell activation are not well understood. In this report, it is shown that both LPS mediated B cell proliferation and IL-6 secretion are dependent on phosphatidylinositol 3-kinase (PI 3-kinase) signaling pathways. The B cell specific co-receptor, CD19 is not tyrosine phosphorylated in LPS stimulated B cells. Thus, in contrast to B cell antigen receptor (BCR) signaling, the activation of PI 3-kinase appears not to be related to the recruitment of PI 3-kinase to tyrosine phosphorylated CD19. This is the first demonstration of the importance of PI 3-kinase signaling pathway in LPS mediated B lymphocyte activation.
Venkataraman
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C
Department of Microbiology and Immunology, Sanders-Brown Research Center on Aging, University of Kentucky, Lexington 40536, USA.
Shankar
G
G
Sen
G
G
Bondada
S
S
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D018941:Antigens, CD19 / Q000378:metabolism; D001402:B-Lymphocytes / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011947:Receptors, Antigen, B-Cell / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D000077191:Wortmannin
D000730:Androstadienes; D018941:Antigens, CD19; D004791:Enzyme Inhibitors; D015850:Interleukin-6; D008070:Lipopolysaccharides; D011947:Receptors, Antigen, B-Cell; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; D000077191:Wortmannin