White blood cell and lymphocyte populations following interleukin-2 administration in the spontaneously hypertensive rat.

The immune system has been linked to the pathogenesis of hypertension in the spontaneously hypertensive rat (SHR). Recently interleukin-2 has been reported to inhibit the development of hypertension in the SHR, but no measures of different lymphocyte populations were made. To test the effect of interleukin-2 we repeated the protocol in the report by injecting forty two day old, male SHR and WKY rats, and in addition, analyzed lymphocyte subpopulations. Untreated, age matched rats of the same strain were used as a control. At three and four months of age blood was drawn from all animals. Monoclonal antibodies were used to fluorescently label different lymphocyte subpopulations. The populations examined were the total T-cells, T-nonhelper cells, T-helper cells and B-cells. Total numbers of lymphocytes and white blood cells were also examined. Blood pressures were measured in conscious, restrained animals at two and four months of age. The results showed no attenuation of blood pressure in the interleukin-2 treated SHR at either age. The interleukin-2 treated SHR had a decrease in the percentage of B-cells and an increase in the percentage of T-nonhelper cells relative to the control SHR. Both treated and untreated SHR had increased numbers of white blood cells and lymphocytes compared to both groups of WKY. We conclude that the interleukin-2 used was active but failed to have any effect on blood pressure or absolute numbers of white blood cells and lymphocytes in the treated animals.