Effect of anti-IgE antibodies on IgE binding to CD23

Human sera contain anti-IgE autoantibodies. Using a human B lymphoblastoid cell line (Wil-2WT cells) and monoclonal murine anti-IgE antibodies (BSW17 and Le27) we investigated a possible role of such anti-IgE antibodies. A 100-fold excess of monoclonal anti-IgE antibodies inhibited binding of 125I labeled IgE to Fc epsilon RII on Wil-2WT cells. Further, both monoclonal anti-IgE antibodies dissociated surface bound IgE from Fc epsilon RII on Wil-2WT cells. However, BSW17 which does not trigger histamine release from human leucocytes, was much more effective in dissociating Fc epsilon RII bound IgE than Le27 which triggers histamine release. These results may suggest that naturally occurring IgG anti-IgE antibodies are able to inhibit binding of IgE to its receptor.