IgM receptors on human lymphocytes: detection by direct binding.

Abstract
Radioiodinated Ig[immunoglobulin]M isolated from a patient with Waldenstrom macroglobulinemia binds with high avidity (apparent Ka = 2.5 .times. 109/M) to freshly isolated human peripheral blood lymphocytes. Binding occurred through the Fc region of the molecule and involved a receptor specific for IgM. The avidity and specificity of this binding are consistent with a biologic role for IgM receptors on lymphocytes.