Surface immunoglobulin D (SIgD) and receptors for C3b (CR1) were demonstrated to be closely associated at the surface of mouse spleen lymphocytes. When SIgD was modulated by incubation at 37°C with heteroantisera (rabbit) or monoclonal alloantibodes specific for δ-chains, the number of splenocytes capable of forming rosettes with EAC-3b decreased by about 40%, whereas a smaller effect (13%) could be observed when EAC1-3d (indicators for CR2) were used. Antibodies to surface IgM were not inhibitory, ruling out the possibilty of nonspecific inhibition of the C receptor sites by antigen-antibody complexes formed at the cell surface. In addition, co-capping of IgD and CR1 was observed on 65% of the cells expressing both markers. In these experiments IgM was shown to redistribute independently from both CR1 and CR2. Cr2 and IgD also capped independently. Taken together with the observations that IgD and CR are ontogenitically related and that they have in common certain biologic properties (such as sensitivity to proteolytic enzymes and rate of turnover), these data suggest a functional relationship between the 2 surface receptors. A possible role in mechanism mecahnism of B lymphocyte triggering is discussed.
|Number of pages||6|
|Journal||Journal of Immunology|
|Publication status||Published - 1981|
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