Demonstration of receptors for insulin-like growth factor-II on human T-lymphocytes.
Primary human T-lymphocytes that have been mitogen activated in chemically defined medium demonstrate cell surface receptor for insulin-like growth factor-II (IGF-II). In contrast resting T-lymphocytes demonstrate little or no IGF-II receptor. Receptors appear within 24 hours of mitogen activation with maximal binding occurring at 72 hours. After this point IGF-II binding declines. Receptor binding of IGF-II to T-lymphocytes does not show a sharp pH dependence but is maximal above pH 7. Insulin does not compete for IGF-II binding sites and proinsulin competes only weakly, suggesting that this is a type 2 IGF receptor and not an insulin receptor. Furthermore, anti-insulin antibodies do not inhibit IGF-II from binding to activated T-lymphocytes indicating divergent binding domains on the two peptide hormones. IGF-II demonstrates stimulating action on T-lymphocyte proliferation probably mediated by binding of IGF-II to this receptor.
D002478:Cells, Cultured; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D007700:Kinetics; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins / Q000494:pharmacology; D011972:Receptor, Insulin / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*
D007328:Insulin; D010835:Phytohemagglutinins; D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D013002:Somatomedins; D007335:Insulin-Like Growth Factor II; D011972:Receptor, Insulin