The structure of two IgMs showing different activity from a patient with Waldenstrom's macroglobulinaemia

Abstract

SUMMARYThe two monoclonal IgMs (IgM I and lgM2) were characterized from a patient with Waldenstrom's macroglobulinaemia that rcsullcd in a gamniapathy. Heavy and light chains were isolated from Ihe IgM. The complete primary structure ofthe two light chains and the NH;-tcrminal region of the iwo heavy chain molecules were determined. The sequence dala indicated that the heavy and light chains from bolh IgMs belong to the same (III and II) lambda subgroups. By testing their antibody activity it was found by imtiiunonuorescencc and immunoblotting that only IgM2 reacts with an intermediate filament protein.