Expression of heat shock proteins 65, 72 and 90 in mercuric chloride-treated human peripheral blood mononuclear cells

Peripheral blood mononuclear cells (PBMC) were challenged with different co ncentrations 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 int o DNA. Hsp 55 immunoreactivity was peripherally located in the cells at a m ercuric chloride concentration of 5.5-2.8x10(-5) mol/L, which also gave a d ecreased DNA synthesis. Hsp 72 positive cells, with a nuclear and cytoplasm ic immunoreactivity, were found ata concentration of 5.5-2.2x10(-5) mol/L. Hsp 90 positive cells also with an immunoreactivity at a nuclear and cytopl asmic level, were found at 1.1x10(-5)-5.5x10(-6) mol/L. A stimulated DNA sy nthesis was obtained already at 2.2x10(-5) mol/L and was found down to 5.5x 10(-6) mol/L. High concentrations of mercuric chloride might induce express ion of hsp 65 and 72 as a protective mechanism. Hsp 90 as well. as hsp 72 m ight be involved in the proliferation of human PBMC to mercuric chloride. T hus, this expression of hsp 72 may have a dual role.