IGM RECEPTORS ON HUMAN LYMPHOCYTES - DETECTION BY DIRECT BINDING

Radioiodinated IgE isolated from a patient with Waldenstrom macroglobulinemia binds with high avidity (apparent K(a) = 2.5 x 10-9 M-1) to freshly isolated human peripheral blood lymphocytes. Binding occurred through the Fc region of the molecule and involved a receptor specific for immunoglobulins of the IgM class. The avidity and specificity of this binding are consistent with a biologic role for IgM receptors on lymphocytes.