Search

It is now well documented that the mode of primary stimulation in the mouse determines the ratio of Th1-, Th0- or Th2-type T cells obtained. In this paper we determine whether driving and cloning human peripheral blood mononuclear cells (PBMC) non-specifically with interleukin-2 (IL-2) and/ or IL-4 and mitogen, will differentially select T cells for IL-10 production. The presence of IL-2 during culture (with or without IL-4) yielded predominantly Th1-type clones (81% of clones with IL-2 alone and 77% with IL-2 + IL-4) and a low frequency of Th0-type clones (19% of clones with IL-2 and 10% of clones with IL-2 + IL-4), whereas IL-4 alone increased the yield of the IL-4 producing Th0 (35%) clones. The proportions of IL-2-producing clones did not alter with treatment; however, the combination of IL-2 + IL-4 altered the proportions of IL-10-producing clones. 47% of IL-2-cultured cells and 51% of IL-4-cultured cells produced IL-10 respectively, whereas only 22% of clones driven with IL-2 + IL-4 produced detectable levels of IL-10. Thus in the preliminary experiments described here we have demonstrated that the cytokines used to initially drive out human T cells and maintain the T-cell growth can skew the Th1/Th2/Th0 cytokine profiles of the clones obtained from mitogen-stimulated cultures. Moreover and unexpectedly the proportion of IL-10-producing cells is altered. These results are important in interpreting analysis of the cytokine profiles of human T cells and raise questions concerning how we should derive T-cell clones for a cytokine analysis that truly reflects the in vivo situation. [ABSTRACT FROM AUTHOR]

CD27 is a T-cell surface antigen expressed on the majority of peripheral T cells and belongs to a newly defined receptor family including the iow-affinity nerve growth factor receptor, tumour necrosis factor (TNF) receptors, the B-cell activation antigen CD40, and the Fas antigen. Although the function of CD27 has not been defined, several experimental observations support the notion that this molecule plays an important role in the process of T-cell activation. In this paper, we have demonstrated that a rapid hyperphosphorylation of CD27 is induced by a cyclic AMP-inducing agent, forskolin, and a membrane-permeable cAMP analogue, 8-bromo-cAMP, as well as phorbol 12-myristate 13-acetate (PMA). In addition, increased phosphorylation of CD27 in T-cell activation either via CD2 or CD3 pathways was strongly suppressed by a cyclic nucleotide-dependent kinase inhibitor, H-8, but only slightly by a protein kinase C inhibitor, staurosporine. These results suggest that protein kinase A might be a key kinase responsible for CD27 phosphorytation in the process of T-cell activation. CD27 is the first T-cell surface antigen demonstrated to be phosphorylated by the cyclic AMP-protein kinase A-mediated pathway. [ABSTRACT FROM AUTHOR]