Expression of Heat Shock Proteins 65, 72 and 90 in Mercuric Chloride-Treated Human Peripheral Blood Mononuclear Cells

Abstract

Peripheral blood mononuclear cells (PBMC) were challenged with different concentrations of mercuric chloride and the expression of heat shock protein (hsp) 65, 72 and 90, were investigated by an indirect peroxidase method as well as the proliferation was measured by uptake of tritiated thymidine into DNA. Hsp 65 immunoreactivity was peripherally located in the cells at a mercuric chloride concentration of 5.5–2.8×10⁻⁵ mol/L, which also gave a decreased DNA synthesis. Hsp 72 positive cells, with a nuclear and cytoplasmic immunoreactivity, were found at a concentration of 5.5–2.2×10⁻⁵ mol/L. Hsp 90 positive cells also with an immunoreactivity at a nuclear and cytoplasmic level, were found at 1.1×10⁻⁵–5.5×10⁻⁶ mol/L. A stimulated DNA synthesis was obtained already at 2.2×10⁻⁵ mol/L and was found down to 5.5×10⁻⁶ mol/L. High concentrations of mercuric chloride might induce expression of hsp 65 and 72 as a protective mechanism. Hsp 90 as well as hsp 72 might be involved in the proliferation of human PBMC to mercuric chloride. Thus, this expression of hsp 72 may have a dual role.