Evaluation of T cell subpopulation and function in thymosin treated spontaneously hypertensive rats

Recent evidence of immunologic abnormalities in the spontaneously hypertensive rat (SHR) have been reported as one of the underlying causes in the pathogenesis of hypertension. In this study, monoclonal antibodies were used in a direct immunofluorescence assay to analyze the percentage of lymph node T cell subsets in untreated controls compared to thymosin treated SHR and Wistar Kyoto (W/K) rats. Results indicated that there were 19.7% T helper cells in the lymph nodes of the untreated SHR and 10.8% in the W/K, while the SHR suppressor population was 15.5% and the W/K 24.4%. Administration of thymosin, fraction 5 or the thymosin peptide alpha 7 increased suppressor cell number 2.5 to 3 fold and was successful in lowering blood pressure. Use of the Alzet mini-osmotic pump, containing a 2 week supply of thymosin, fraction 5 or alpha 7, was also effective in lowering blood pressure. In addition, thymosin treatment increased plaque forming cells approximately 2 to 6 fold in both SHR and W/K animals depending on the mode of administration. Female rats were more responsive to treatment with thymosin than male rats.