Human organ-specific autoimmune disease. Molecular cloning and expression of an autoantibody gene repertoire for a major autoantigen reveals an antigenic immunodominant region and restricted immunoglobulin gene usage in the target organ.

Abstract

The most common organ-specific autoimmune disease in humans involves the thyroid. Autoantibodies against thyroid peroxidase (TPO) are present in the sera of virtually all patients with active disease. We report the molecular cloning of the genes for 30 high-affinity, IgG-class human autoantibodies to TPO from thyroid-infiltrating B cells. Analysis of the putative germline genes used for the TPO human autoantibodies suggests the use of only five different H and L chain combinations involving four H chains and three L chains. In addition, the same combination of H and L chains was found in multiple patients. The F(ab) proteins expressed by these genes define two major, closely associated domains (A and B) in an immunodominant region on TPO. These A and B domains contain the binding sites of 80% of IgG-class TPO autoantibodies in the sera of patients with autoimmune thyroid disease. The present information permits analysis, not previously possible, of the relationship between autoantibody H and L chain genes and the antigenic domains on an autoantigen. Our data, obtained using target organ-derived autoantibodies, indicate that there is restriction in H and L chain usage in relation to the interaction with specific antigenic domains in human, organ-specific autoimmune disease. (J. Clin. Invest. 1993. 92:62-74.)

Thyroid peroxidase autoantibody epitopic ‘fingerprints’ in juvenile Hashimoto’s thyroiditis: evidence for conservation over time and in families

“…In agreement with the previous observation that the recombinant Fab recognized immunodominant epitopes [8], the Fab inhibited the binding to TPO of serum autoantibodies in most (7/9) patients by more than 80% (Table 1). For two patients, at different time intervals, 32-60% of serum TPO autoantibodies were to the immunodominant region.…”

Human Anti-Thyroid Peroxidase Single-Chain Fragment Variable of Ig Isolated from a Combinatorial Library Assembled In-Cell: Insights into the In Vivo Situation

“…Several TPO Fabs have been produced using either bacteriophage vector (7,9) or phage display vector pComb3 (10,11,16,35,36). Despite the fact that individual H and L chain genes of the TPO Fab already described are clearly those used in vivo, it has yet to be proved whether separate amplification of heavy and light chains and their random recombination produce the same H and L chains pairing as in vivo.…”

“…3), recombinant human Ab fragments have been produced using phage library technology (4 -6). Several groups have used this technology to generate specific human anti-TPO Fabs (7)(8)(9)(10)(11). These Fabs have been widely analyzed in terms of epitope specificity and variable genes usage.…”

Search for the Autoantibody Immunodominant Region on Thyroid Peroxidase: Epitopic Footprinting with a Human Monoclonal Autoantibody Locates a Facet on the Native Antigen Containing a Highly Conformational Epitope

“…Serum TPO autoantibodies, the primary markers of thyroid autoimmunity (1), are likely to be involved in autoantigen presentation to T cells (2,3) and may also play a direct role in the process leading to thyroid cellular destruction (4,5). The molecular cloning and expression of TPO autoantibody genes have made available a panel of recombinant, monoclonal human TPO autoantibodies that define a restricted, immunodominant region on TPO (6,7). Elucidation of the structure of this immunodominant region will provide important information for further understanding the immunopathologic mechanisms leading to autoimmune thyroiditis and may facilitate strategies for immunotherapeutic intervention.…”