The lack of competition between two unrelated IgE antibodies in in vivo sensitization of mouse mast cells.

The relation between IgE antibodies of different specificity in in vivo sensitization of mouse mast cells were studied. In the system of active immunization with EA and KLH mixed with Al(OH)3 no inhibition of an IgE and IgGl response to one antigen by simultaneous administration of other antigen was observed. The lack of inhibition was reflected in serum anti-EA and anti-KLH antibody levels as well as in mast cell sensitization expressed in antigen-induced histamine release. Furthermore, we were unable to detect an inhibitory effect of active immunization of mice with EA on in vivo passive sensitization of peritoneal mast cells. These observations indicated that in such a system immunization actively produced IgE antibodies do not saturate mast cell IgE receptors and do not inhibit subsequent sensitization of these cells with IgE antibodies of another specificity.