title: Inhibition of mitogen-activated proliferation of human lymphocytes by hypochlorous acid in vitro: protection and reversal by ascorbate and cysteine.
abstract: Hypochlorous acid (HOCl) at concentrations of 6.25 microM and greater caused statistically significant, dose-related inhibition of mitogen-activated proliferation of human mononuclear leucocytes (MNL). The anti-proliferative effects of HOCl, which were evident using both undepleted and adherent-cell depleted MNL, could not be attributed to decreased mitogen binding by HOCl-treated cells. The anti-oxidants ascorbate and cysteine (50 microM), when added to MNL prior to exposure to HOCl (25 microM), prevented the anti-proliferative effects of the oxidising agent. Likewise reversal of oxidant-mediated inhibition of the responsiveness of MNL to mitogens was observed when ascorbate and cysteine were added after HOCl treatment of the cells. These results suggest that HOCl, derived from activated phagocytes, is a potential mediator of immunosuppression, especially in the setting of abnormal host anti-oxidant defences.
authors.affiliation: Department of Medical Microbiology, (Faculty of Medicine), University of Pretoria, Republic of South Africa.
authors.forename: M J
authors.initials: MJ
authors.lastname: Smit
authors.forename: R
authors.initials: R
authors.lastname: Anderson
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003208:Concanavalin A / Q000378:metabolism; D003545:Cysteine / Q000494:pharmacology*; D006801:Humans; D006997:Hypochlorous Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects*; D008934:Mitogens / Q000037:antagonists & inhibitors*
chemical_list: D007457:Iodine Radioisotopes; D008934:Mitogens; D003208:Concanavalin A; D006997:Hypochlorous Acid; D003545:Cysteine; D001205:Ascorbic Acid