In vitro synthesis of IgE by human peripheral blood leucocytes: V. Functional heterogeneity within the IgE-B-cell pool.

Fractionation of human peripheral blood leucocytes (PBL) B cells by differential sedimentation on a discontinuous Percoll gradient separates B cell subpopulations which vary markedly in rates of spontaneous IgE synthesis, often revealing the presence of active IgE secreting cells which are totally suppressed within unfractionated PBL B cell preparations. The production in vitro of IgE by separated B cell populations from the same individual may respond disparately to an identical population of autologous T cells and to pokeweed mitogen. Kinetic studies revealed major differences in both the rates of release of cell-associated IgE between these B cell populations, and their rates of de novo IgE synthesis. From a methodological viewpoint, the use of this B cell fractionation technique is demonstrated to improve greatly the efficiency of detection of T cell-responsive IgE producing B cells in peripheral blood from atopics, and from a mechanistic standpoint raises the possibility that B cell heterogeneity may modulate the functional expression of IgE-regulatory T cells signals.