Chemical studies of heavy chains of two IgGl-λ myeloma proteins from a single patient

Abstract

Two IgGl-λ myeloma proteins of differing electrophoretic mobility were isolated from the serum of a single patient. The heavy chains of these two proteins were shown to be identical by criteria of N-terminal amino acid sequence, peptide maps, electrophoretic mobility in both acidic and alkaline urea starch gels, amino acid composition and lack of sialic acid. This data is compatible with the view that multiple germ line genes exist coding for the variable regions of immunoglobulin polypetide chains, and supports the concept that a genetic switch mechanism may be operative during the cytodifferentiation of immunocytes.