Secretion of IgE-Specific Potentiating Factors by Human FcεR+ T Cell Lines

In the present study, FceR+ and FceR–– T cells were isolated from patients with the hyper-IgE syndrome and maintained in long-term cultures with interleukin 2. Supernatants from the FceR+ but not from the FceR–– T cell lines enhanced IgE but not IgG synthesis in B cells derived from patients with allergic rhinitis. There was, however, no induction of IgE synthesis in B cells from nonatopic donors. The IgE-potentiating factors bound to IgE-Sepharose but not to IgG-Sepharose. The target B cells for these IgE binding factors appear to be preactivated IgE-bearing B cells.