Qualitative differences between dimeric and trimeric stimulation of human basophils.

Previous studies from this laboratory demonstrated differences between antigenic and anti-IgE antibody stimulation of human basophils under the pharmacologic control of indomethacin. We show here that this difference may be due to the type of aggregation these stimuli induce on the cell surface. We found that the synthetically cross-linked trimer of IgE caused histamine release that was enhanced by indomethacin, whereas dimeric IgE induced-release was not. This result was not due to a difference in the kinetics of release by these two stimuli. These results suggest that the state of aggregation of Fc receptors differentially affects various cellular enzyme systems.