INTERACTIONS BETWEEN LYMPHOCYTE MEMBRANE MOLECULES .2. CHARACTERIZATION OF AN INTERACTION BETWEEN LYMPHOCYTE-B SURFACE IGD AND FC IGG RECEPTORS THAT DIFFERS FROM THE SURFACE IGM-FC IGG RECEPTOR INTERACTION

  • 1 January 1982
    • journal article
    • research article
    • Vol. 128  (3) , 1271-1277
Abstract
Mouse B lymphocyte surface membrane IgD (sIgD) and Fc IgG receptors (Fc.gamma.R) were evaluated for interactions by means of immunofluorescence. Ligand-[F(ab'')2 anti-.delta.] induced capping of sIgD resulted in co-capping of Fc.gamma.R if the latter were occupied during the capping process by soluble antigen-antibody complexes (which themselves provided insufficient cross-linking to result in capping), but not if the Fc.gamma.R were occupied by monomeric IgG or unoccupied. Capping of Fc.gamma.R by highly cross-linked complexes did not cause co-capping of sIgD occupied by monomeric F(ab'') anti-.delta.. The interaction between sIgD and Fc.gamma.R was specific in that cross-reactions between ligands were excluded and ligand-induced capping of sIgD did not cause co-capping of ligand-occupied sIgM or I-A antigens. The sIgD-Fc.gamma.R interaction occurred on only .apprx. 60% of B lymphocytes, and this B cell subpopulation did not correlate with other B cell subpopulations (CBA/N strain B cells and B cells bearing either large or small amounts of sIgD). The sIgD-Fc.gamma.R interaction differed from the sIgM-Fc.gamma.R interaction in that co-redistribution of the latter 2 receptors was induced by F(ab'')2 anti-.mu. when the Fc.gamma.R was occupied by monomeric IgG and involved nearly all B lymphocytes. The qualitative and quantitative differences between the sIgD-Fc.gamma.R and sIgM-Fc.gamma.R interactions suggest a mechanism whereby the 2 antigen receptors could provide different signals to the B lymphocyte.

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