Cell-surface expression of heat shock proteins in dog neutrophils after oxidative stress

The effect of oxidative stress induced by different concentrations of hydro gen peroxide on dog neutrophils was studied. This effect was measured using dichlorofluorescein-diacetate (DCFH-DA) and by the cell surface membrane e xpression of heat shock protein (HSP) 27 kDa, HSP 72 kDa and HSP 90 kDa fam ilies. Hydrogen peroxide induced a concentration-dependent increase in DCFH oxidation (from 10(-6) M to 10(-4) M), and an increase in the cell surface expression of HSPs families. At a concentration of 10-4 hi, the percentage of positive cells that showed an oxidation of DCFH was 94.7% +/- 5.2 (n = 3). Only vitamin E (but not vitamin C) at a concentration of 0.5 mM was abl e to inhibit the intracellular oxidative stress induced by hydrogen peroxid e. The percentage of positive cells that express these proteins after the t reatment with hydrogen peroxide (10-4 M) was: 74% +/- 3.5 for HSP 27, 72% /- 2.6 for HSP 72 and 73% +/- 1.2 for HSP 90 (n = 3). This cell surface exp ression was not abolished by either vitamin C or vitamin E. Localization of HSPs in plasma membrane is of immunological interest because they have bee n implicated in autoimmune diseases. (C) 1999 Elsevier Science Ltd. All rig hts reserved.