Functional and phenotypic properties of T-cell clones which regulate IgE synthesis

We have generated a panel of T-lymphocyte clones from a patient suffering from the hyper IgE syndrome, and have attempted to correlate the ability of each to help IgE responses in vitro with the profile of lymphokines secreted after mitogenic stimulation. Clones which showed positive IgE helper activity released larger amounts of interleukin-4 (IL-4) than the non-helpers, which tended to release more interleukin-2 (IL-2). Surprisingly, all clones released moderate amounts of gamma interferon (IFN), which has been shown to inhibit the action of IL-4 on B cells. The clones were analysed by indirect immunofluorescence using monoclonal antibodies to CDw29 and CD45R (4B4 and 2H4 respectively). Those T cells which could provide strong helper activity for all isotypes, expressed high levels of CDw29 and low CD45R. These data suggest that these CD4-positive T cells expressing surface antigen of the 'memory' subset i.e. CDw29, are involved in IgE isotype regulation by virtue of their ability to secrete IL-4 upon antigenic stimulation.