Immunochemical characterization of the reaction between IgA₁-κ type M-protein with cellulose acetate (Separax-SP) membranes

Abstract

The reaction of a human IgA₁-κ type M-protein with cellulose acetate (Separax-SP) membrane is described. When a membrane consisting of diacetylcellulose and triacetyl cellulose (1:1) was used, the M-protein showed a reactivity with this membrane. The IgA₁ molecules were found to have a molecular weight of 170, 000 and composed of two α₁ chains of about 64, 000 and two κ chains of 23, 000. Since the patient's αFab and αFc alone can not induce reactions on Separax-SP, this suggests that the reaction of the M-protein with the membrane can not be ascrived to the antigen-antibody reaction. The possibility exists that the reaction between acetyl cellulose of the Separax-SP membrane and the patient's M-protein is due to a physical steric reactivity. The present case seems to be the first report of IgA₁-κ type M-protein which reacts with Separax-SP membranes.