In vitro production of IgE in humans: kinetic studies and analysis of serum enhancing and inhibitory factors.

By using a sensitive and reliable method for the measurement of IgE produced in vitro by peripheral blood lymphomonocytes, the following observations may be made. Serum obtained from atopic donors shows a significant capacity to enhance the in vitro synthesis of IgE of PBL from atopic as well as of non-atopic donors. On the other hand, serum obtained from non-atopic donors demonstrates a clear-cut inhibitory effect on IgE synthesis of cells from both atopic and non-atopic individuals. The kinetics of the IgE production was studied. As early as 30 min after initiation of culture, PBL of atopic individuals showed the capacity to synthesize large amounts of IgE. The IgE synthesis continued, with variations from case to case, for 7 days. This capacity of the cells is completely inhibited following incubation of the PBL for a short period of time with a protein synthesis inhibitor, cycloheximide. This in vitro procedure represents a valuable tool for the study and identification of the enhancing and suppressor factors of IgE synthesis present in the serum.