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The human immune response to reconstituted bovine collagen
Abstract:
The human immune response to bovine dermal collagen was characterized through histologic, serologic, and immunoblotting methods. Collagen-sensitive patients were identified by hypersensitivity to intradermal exposure to ZYDERM Collagen Implant--a pepsin-solubilized, reconstituted, bovine dermal collagen. Biopsies of test sites in the forearm were obtained from several collagen-sensitive patients. Histologic examination revealed an implant-associated palisading foreign body granuloma. The lesion also contained a mixed cell infiltrate of histiocytes, lymphocytes, and eosinophils. Sera were collected from patients who developed erythema or induration at intradermal test or treatment sites, and were evaluated for antibodies to bovine dermal collagen by an enzyme-linked immunosorbent assay (ELISA). Sera with anti-collagen antibodies were further characterized in this study. The circulating antibodies were reactive with both native and heat-denatured bovine dermal collagen. By using purified alpha 1(I) and alpha 2(I) polypeptides, these sera were found to have antibodies reactive with both alpha-chains. Each alpha-chain was fragmented by using cyanogen bromide (CB). The CB peptides were electrophoretically separated, and these sera were evaluated for antibodies to the major fragments by using an immunoblotting technique. Of the sera evaluated by this method, 89% (23/26) had antibodies to alpha 1-CB6; 77% (20/26) had antibodies to alpha 2-CB4; and 65% (17/26) had antibodies reactive with both CB fragments. In addition, most sera (77%) contained antibodies reactive with two or more (up to five) of the major CB peptides. The least antigenic fragment was alpha 2-CB3,5 (8%). In addition, these sera had antibody activity against both native and heat-denaturated bovine types III and II collagens. Little or no interspecies (rat or guinea pig) cross-reactivity (types I and II) was detected. Furthermore, these sera did not have antibodies against human types I, II, and III collagens.