Fractionation of human thymocytes and peripheral blood lymphocytes on Percoll density gradients and DNA synthesis stimulating effect of mercuric chloride.

Human thymocytes and peripheral blood lymphocytes were separated on the basis of density on Percoll gradients and the different cell populations tested regarding DNA synthesis after addition of mercuric chloride. Thymocytes with a density of 1.065-1.067 g/ml and peripheral blood lymphocytes with a density of 1.063-1.065 g/ml were maximally stimulated with mercuric chloride as well as with mitogenic lectins. Thus mercuric chloride seems to be a polyclonal activator of human peripheral T lymphocytes and thymocytes with characteristics of medullary cells (virgin T cells).