The interaction of IgE with rat basophilic leukemia cells—VI

Antigen-antibody complexes prepared from rat IgGa inhibited the binding of rat IgE by rat basophilic leukemia cells, but failed to inhibit IgE binding to small membrane particles from such cells. Monomeric IgGa could not be shown to bind to the cells in direct studies and failed to inhibit IgE binding. The results can be rationalized on the basis of a weak intrinsic affinity of IgGa for the receptor for IgE which is amplified by extensive multipoint attachement.