Amino acid sequence similarities in two human anti gamma globulin antibodies

Certain individuals with hypergammaglobulinemic purpura contain in their serum anti gamma globulins of restricted heterogeneity. These antibodies, characteristically of the gammaG type, were isolated from two unrelated individuals and their light polypeptide chains were subjected to amino acid sequence analysis. Although these anti gamma globulin antibodies conform to the basic VK(1) sequence, substitutions not previously encountered were found in five positions. The two antibodies were identical with each other up to residue 40 from the N-terminus of the light chains.