Production and Characterization of Two Monoclonal Antibodies to Human Glutathione Peroxidase

Glutathione peroxidase (GSH—Px) is an important selenium—containing enzyme which protects cells from oxidative damage. Two hybridoma clones (GPX—121 and GPX—347), producing mouse IgGl monoclonal antibodies specific for GSH—Px, were established. Immunoblot analysis revealed that GPX—347 was specific for human GSH—Px, while GPX—121 cross—reacted with human, rat, mouse and rabbit GSH—Px. Correlation between GSH—Px content and its enzymatic activity was investigated in erythrocytes of 76 humans and in human lung adenocarcinoma PC—9 cells by using a sandwich type ELISA. The results indicated that GSH—Px activity was expressed higher than expected from GSH—Px content especially in the range of low GSH—Px concentration. PC—9 cells were stained immunohistochemically using GPX—347 monoclonal antibody. PC—9 cells grown in selenium depleted medium did not stain but the cytoplasm of PC-9 cells grown in medium supplemented with selenium stained strongly.