Immunogenicity of a brominated protein and successive establishment of a monoclonal antibody to dihalogenated tyrosine

During inhalation of allergens and experimental sepsis, formation of brominated tyrosine has been reported. In this study, we first examined the immunogenicity of brominated protein prepared by treatment of N-bromosuccinimide (NBS). The immunized serum obtained reacted with brominated bovine serum albumin (BSA). The NBS dose-dependent formation of immunoreactivity, which was estimated by enzyme-linked immunosorbent assay, was observed, and the increase coincided with 3,5-dibromotyrosine (DiBrY) formation in the modified BSA, which was chemically determined by liquid chromatography/quadrupole tandem mass spectrometry (LC/MS/MS). Second, by use of immunized mice, monoclonal antibodies to the brominated one were prepared. The two established novel monoclonal antibodies obtained from the immunized mice reacted with DiBrY, 3,5-dichlorotyrosine (DiClY), and 3,5-diiodotyrosine (DiIY). Moreover, 3,5-dihalo-4-hydroxybenzoic acids (3,5-dichloro-4-hydroxybenzoic acid and 3,5-dibromo-4-hydroxybenzoic acid) were recognized by these antibodies. These results suggest that dihalogenated tyrosines (DiBrY, DiClY, and DiIY) are the epitopes. Lastly, we used the antibody in an immunohistochemical study. Lipopolysaccharide (LPS) was intraperitoneally administered to mice, and livers were removed. Positive staining of LPS-treated mouse liver tissues by both the anti-dihalotyrosine antibody and anti-myeloperoxidase antibody was estimated, suggesting that inflammatory tissue damage induces the formation of dihalotyrosine in vivo.