PERIPHERAL-BLOOD BASED T-CELL-CONTAINING AND T-CELL-DEPLETED CULTURE SYSTEMS FOR HUMAN IGE SYNTHESIS - THE ROLE OF T-CELLS

Background Comparable T cell-containing and T cell-depleted culture sy stems for human IgE synthesis are currently not available. Objective T his has prompted us to develop peripheral blood mononuclear cell (PBMC ) based culture systems for human IgE synthesis in the presence and ab sence of T cells. Methods In this paper we describe simplified conditi ons for in vitro synthesis of high levels of IgE by human peripheral b lood B cells, both in T cell-containing cultures and in anti-CD40 stim ulated T cell-depleted cultures. Results T cell-depleted cultures rele ased approximately 20 times more IgE [range 410-2220 ng/mL (mean 1270 ng/mL); based on six experiments using cells from three donors] than d id T cell-containing cultures [range 23-105 ng/mL (mean 58 ng/mL); bas ed on 15 experiments using cells from three donors]. Reconstitution ex periments were performed to investigate the role of T cells on IgE syn thesis. Adding T cells back to the anti-CD40 stimulated T cell-deplete d cultures resulted in a dose-dependent inhibition of IgE production. In the absence of anti-CD40 low numbers of T cells stimulated, while h igh numbers suppressed, IgE production: the optimal ratio of T cells t o non-T cells for maximal IgE production was found to be 1:1. At this ratio, irradiated (non-replicating) T cells supported a much greater I gE synthesis than did non-irradiated T cells. Conclusion The developme nt of these systems provides directly comparable T cell-containing and T cell-depleted cultures for human IgE synthesis from peripheral bloo d, allowing further study of the role of T cells in IgE regulation. Th ese systems will also be of use for determining whether potential modu lators of IgE synthesis act on the T cells or on other cell types.