PMID: 7545950Sep 15, 1994Paper

Production and nucleotide sequence of an inhibitory human IgM autoantibody directed against platelet glycoprotein Ia/IIa.

Blood
H DeckmynJ Vermylen

Abstract

Human B-cell lines were derived by limiting dilutions of Epstein-Barr virus (EBV) transformed peripheral B cells from a patient with an autoantibody against glycoprotein (GP)Ia/IIa, and manifesting defective collagen-induced platelet aggregation and a bleeding problem. Antibody-producing clones were selected for their reactivity with whole platelets or with affinity-purified GPIa/IIa by enzyme-linked immunosorbent assay (ELISA). One of these cell lines, selected for further evaluation, produced an IgM (E3G6) that interfered with platelet aggregation responses. Polymerase chain reaction (PCR) amplifications with two different sets of primers specific for human kappa-chains resulted in the rescue of a unique and identical sequence. The same was true for the mu-chain, from which it was concluded that the cell line was monoclonal. Further analysis showed that the kappa variable domain sequence is similar to the germline gene A30, to 2E7, an anti-GPIIb human autoantibody, and to HF2-1/17, a systemic lupus erythematosus (SLE)-associated broad-specificity human autoantibody. Thus, the specificity of our antibody, E3G6, appears to be determined by the mu-chain, the sequence of which is encoded by a VHIII gene segment strongly homologou...Continue Reading

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