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Title: Somatic diversification in the heavy chain variable region genes expressed by human autoantibodies bearing a lupus-associated nephritogenic anti-DNA idiotype

Journal Article · · Proceedings of the National Academy of Sciences of the United States of America; (United States)

Monoclonal anti-DNA antibodies bearing a lupus nephritis-associated idiotype were derived from five patients with systemic lupus erythematosus (SLE). Genes encoding their heavy (H)-chain variable (V[sub H]) regions were cloned and sequenced. When compared with their closest V[sub h] germ-line gene relatives, these sequences exhibit a number of silent (S) and replacement (R) substitutions. The ratios of R/S mutations were much higher in the complementarity-determining regions (CDRs) of the antibodies than in the framework regions. Molecular amplification of genomic V[sub H] genes and Southern hybridization with somatic CDR2-specific oligonucleotide probes showed that the configuration of the V[sub H] genes corresponding to V[sub H] sequences in the nephritogenic antibodies is not present in the patient's own germ-line DNA, implying that the B-cell clones underwent somatic mutation in vivo. These findings, together with the characteristics of the diversity and junctional gene elements utilized to form the antibody, indicate that these autoantibodies have been driven through somatic selection processes reminiscent of those that govern antibody responses triggered by exogenous stimuli.

OSTI ID:
7009373
Journal Information:
Proceedings of the National Academy of Sciences of the United States of America; (United States), Vol. 91:2; ISSN 0027-8424
Country of Publication:
United States
Language:
English