Modulating effects of heparin preparations on the DNA synthesis response of human peripheral blood T lymphocytes activated by mercuric chloride and nickel sulfate.

The effect of unfractionated heparin and a low molecular weight heparin fragment was tested on the DNA synthesis response of human peripheral blood T lymphocytes from nickel-allergic patients, activated by mercuric chloride and nickel sulfate. An inhibition was found with unfractionated heparin at a concentration of 1.1 mg/ml, when added at 1 h after mercuric chloride and nickel sulfate and with the same concentration of the heparin fragment, when added at 1 h after nickel sulfate, no effect was seen after addition at 72 h after the salts. Both heparin preparations in concentrations of 0.0001-0.11 mg/ml stimulated the response to nickel sulfate and in concentrations of 0.001-0.11 mg/ml stimulated the response to mercuric chloride. Thus the heparin preparations seem to have different modulating effects on both nickel and mercury activation of lymphocytes dependent on both heparin concentration and the point of time when it was added in the course of the activation process.