Binding of different ligands to IgM-Fc receptors of rat leucocytes.

The primary receptor ligand interaction between rat leucocyte membrane receptors for IgM and their ligands were examined. We found that the incubation time for optimal IgM binding is different on the two types of IgM-Fc receptor-bearing spleen cells and peritoneal macrophages. The investigation of cytophilic activity of polyclonal or monoclonal IgM proteins and their fragments from various species indicated the fine specificity of receptors. Finally, data arc presented which suggest a multiple point co-operative binding between IgM-coated erythrocytes and IgM-Fc receptor-bearing cells. [ABSTRACT FROM AUTHOR]