Immunohistochemical detection of human gastrointestinal glutathione peroxidase in normal tissues and cultured cells with novel mouse monoclonal antibodies

This is the first report to describe the successful detection of human gast rointestinal glutathione peroxidase in normal tissues by Western blotting a nd immunohistochemical staining techniques. Four hybridoma clones producing monoclonal antibodies (MAbs) against the human gastrointestinal glutathion e peroxidase were established from mice immunized with a gastrointestinal g lutathione peroxidase-derived peptide. The MAbs did not crossreact with oth er members of the glutathione peroxidase family, be it cellular glutathione peroxidase, phospholipid hydroperoxide glutathione peroxidase, or extracel lular glutathione peroxidase. Although the MAbs were found to react with a 24-kD protein in a Western blotting assay using gastric carcinoma cell extr acts as antigen, they did not react with a B-lymphoblastoid cell extract. I mmunohistochemical staining showed gastrointestinal glutathione peroxidase localized in the cytoplasm and in the nucleus of gastric carcinoma cells. M oreover, gastrointestinal glutathione peroxidase was detected in tissue ext racts of human stomach, small intestine, large intestine, liver, and gallbl adder by Western blotting, and its localization was immunohistochemically c onfirmed in the mucosal epithelia of the basal area of gastric pits and int estinal crypts.