LIGHT AND HEAVY-CHAINS SPECIFYING A HUMAN IGM-KAPPA AUTOANTIBODY TO AT-CELL RECEPTOR V-BETA-ANTIGEN

Humans frequently produce serum IgM autoantibodies reactive with T-cel l receptor beta chains at a determinant defined by peptides correspond ing to the first complementarity determining region. It is likely that this determinant serves as a public idiotype involved in immunoregula tion. Following screening of culture supernatants from over 60 Epstein -Barr virus-carrying B-cell lines of normal and neoplastic origin, we identified a line, IARC307, that secretes an IgM kappa protein showing marked specificity for the V beta 8.1 CDR1 sequence CKPISGHNSLFQWYRQT . We cloned and sequenced the complete variable regions of the V kappa and V-H chains used by the autoantibody. The light chain has a V kapp a III sequence related to the 'a' subgroup and uses J kappa 2. The hea vy chain has a VHIII sequence essentially identical to the germline se quence DP54 and uses the J(H)6C minigene. The CDR3 is unique, differin g from those of other autoantibodies. The antibody is rigorously speci fic in its specificity for the V beta 8 peptide and does not show poly specificity for protein or DNA antigens.