Open AccessMolecular heterogeneity of antigen‐ or idiotype‐induced anti‐thyroglobulin monoclonal autoantibodies
Author(s) -
BEDIN C.,
ROPARS A.,
MIGGODEFROY K.,
CHARREIRE J.
Publication year - 1995
Publication title -
clinical & experimental immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.329
H-Index - 135
eISSN - 1365-2249
pISSN - 0009-9104
DOI - 10.1111/j.1365-2249.1995.tb03723.x
Subject(s) - idiotype , autoantibody , epitope , thyroglobulin , monoclonal antibody , monoclonal , biology , immunology , antigen , microbiology and biotechnology , autoimmune thyroiditis , idiotopes , autoimmunity , antibody , thyroiditis , genetics , thyroid
SUMMARY To define the molecular basis of the cognitive interaction in experimental autoimmune thyroiditis (EAT), we sequenced the variable regions of monoclonal autoantibodies to thyroglobulin (Tg), specific or not for the F40D peptide, a Tg pep tide capable of inducing EAT in CBA/J mice. Three MoAbs were obtained by immunization with syngeneic Tg of CBA/J (3B8G9, 2F6F2) or C57B1/6 (4D11F4) mice. 3B8G9 was specific for F40D peptide, whereas 2F6F2 and 4D11F4 were not. Two others were raised in CBA/J mice by manipulation of idiotypic pathways: B12 resulted from the immunization with one Ab2β, bearing the internal image of one F40D epitope, and TA2 from the immunization with F40D‐specific cytotoxic HTC2 T cells. B12 and TA2 were both specific for F40D. All hybridomas expressed different members of the J558 VH family, except 3B8G9 which expressed a Q52 V H gene segment. These data led us to hypothesize that regulatory anti‐id autoantibodies used members of one V H family located in the 5′‐end of the V H locus, whereas EAT‐associated autoantibodies used a member of one of the most D‐proximal V H family. As expected, no homologies were found when anti‐F40D monoclonal autoantibodies were compared with two other monoclonal autoantibodies displaying a different epitopic specificity. Among the anti‐F40D monoclonal autoantibodies, one histidine residue located in position 35 of the CDRl region was constantly found. Moreover, TA2 and B12 exhibited two common animo acids in their CDR3 regions, one glycine and one tyrosine, in positions 98 and 99, respectively. Striking homologies were found between TA2 and one anti‐polyGAT MoAb, and between 3B8G9 and some anti‐phenyloxazolone (phOx) monoclonal autoantibodies. Lastly, the VK sequence from 4D11F4 was identical at the amino acid level to the VK sequence from another monoclonal autoantibody, 81B1, which was previously raised towards syngeneic Tg in CBA/J mice. Our data imply that anti‐idiotypic regulatory circuits in EAT might be generated by a heterogeneous population of B cells rather than obtained by a single dominant B cell population.