The Journal of Immunology, Vol 142, Issue 9 3158-3163, Copyright © 1989 by American Association of Immunologists

ARTICLES

Structural and idiotypic characterization of the L chains of human IgM autoantibodies with different specificities [published erratum appears in J Immunol 1989 Dec 1;143(11):3864]

FR Goni, PP Chen, D McGinnis, ML Arjonilla, J Fernandez, D Carson, A Solomon, E Mendez and B Frangione
Department of Pathology, New York University Medical Center 10016.

We have determined the V region amino acid sequence and/or serologic markers (kIIIb, PSL2, and PSL3) of 24 IgM monoclonal autoantibodies with specificities of anti-gamma-globulin (RF), anti-I (cold agglutinin), anti-low density lipoprotein and anti-intermediate filaments. The data emphasize the overwhelming selection of the HumKv325/VkIIIb L chain for this family of autoantibodies. The few amino acid substitutions found within the VL regions were mainly concentrated in the complementarity-determining region 1. JK and CK genes did not show the same pattern of restriction. There is a good correlation between the amino acid sequence and the presence of the kIIIb marker. The idiotypic marker PSL2 was present in 34 out of 35 kIIIb L chains analyzed (97%) and the PSL3 in 27 (80%). Moreover, the hydrophilicity and antigenic profiles of these L chains corroborate the presence of the epitopes detected by the anti-CRI. These results demonstrate a restricted selection of the Vk genes used by a family of self reacting proteins, and an unusual evolutionary conservation of the idiotypic structure that may be involved in the network regulation.