title: A role for phosphatidylinositol 3-kinase in generating T cell help for B cell growth and differentiation.
abstract: Evidence supporting the importance of the 3-phosphoinositide signaling pathway in lymphocyte activation is rapidly accumulating. In our study, we assessed the effects of two PI 3-kinase inhibitors, wortmannin and LY294002, on T cells as a means to analyze the role of the PI 3-kinase-signaling pathway in the generation of T cell help for B cell growth and differentiation. For these studies, B cells were cocultured with CD3-activated mitomycin C-treated T cells to induce B cell responsiveness. Of interest, wortmannin or LY294002 pretreatment of the T cell population significantly inhibited T cell-dependent induction of B cell proliferation and differentiation. The failure of wortmannin-treated CD3-activated mitomycin C-treated T cells to provide help in driving the differentiation of B cells to Ig-secreting cells could not be corrected by the addition of exogenous IL-2. Further studies designed to elucidate the mechanism by which wortmannin-treated T cells failed to provide B cell help indicated that wortmannin and LY294002 significantly inhibited the induction of CD40 ligand and, to a lesser extent, intercellular adhesion molecule-1 expression. These results suggest that the PI 3-kinase-signaling pathway, or other wortmannin- and LY294002-sensitive pathways, may be important for the induction of expression of crucial interaction molecules, such as CD40 ligand, on T cells and thus indicates that D-3 phosphoinositides play a pivotal role in regulating T cell-dependent B cell activation.
authors.affiliation: Department of Immunology, Mayo Clinic/Foundation, Rochester, MN 55905, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Aagaard-Tillery
authors.forename: D F
authors.initials: DF
authors.lastname: Jelinek
mesh_terms: D000328:Adult; D000730:Androstadienes / Q000494:pharmacology; D001402:B-Lymphocytes / Q000166:cytology*; D023201:CD40 Ligand; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008211:Lymphocyte Cooperation / Q000187:drug effects / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D002867:Chromones; D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D009025:Morpholines; D023201:CD40 Ligand; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D000077191:Wortmannin