Human IgE antibody synthesis in vitro: stimulation of IgE responses by pokeweed mitogen and selective inhibition of such responses by human suppressive factor of allergy (SFA).

The studies presented herein provide details of an in vitro system in which IgE biosynthesis by human peripheral mononuclear cells can be stimulated by exposure to pokeweed mitogen (PWM). Mononuclear cells of normal donors or patients with hyperimmunoglobulinemia E were cultured in 2 stages, the first stage consisting of exposure of cells to stimulating mitogen; after this first stage incubation, cells were washed and replated in cultures devoid of any additional mitogen for a further 6 days. Under such conditions, human mononuclear cells were shown to synthesize significant quantities of IgE. Both T cells and surface IgE-bearing cells were shown to be necessary in order to obtain an IgE response in this system. Supernatants from 2-way human mixed lymphocyte cultures were shown to contain an IgE class-specific suppressive factor capable of selectively inhibiting in vitro IgE (and not IgG) biosynthesis. This model can be used to compare the regulation of IgE synthesis in normal and atopic donors, and further experiments examining the production and action of this class-specific suppressive factor may have prognostic and therapeutic implications.