Adaptive immune response has been implicated in inflammation and fibrosis as a result of exposure to mineralocorticoids and a high-salt diet. We hypothesized that in mineralocorticoid-salt-induced hypertension, activation of the mineralocorticoid receptor alters the T-helper 17 lymphocyte (Th17)/regulatory T-lymphocyte/interleukin-17 (IL-17) pathway, contributing to cardiac and renal damage. We studied the inflammatory response and tissue damage in rats treated with deoxycorticosterone acetate and high-salt diet (DOCA-salt), with or without mineralocorticoid receptor inhibition by spironolactone. To determine whether Th17 differentiation in DOCA-salt rats is caused by hypertension per se, DOCA-salt rats received antihypertensive therapy. In addition, to evaluate the pathogenic role of IL-17 in hypertension and tissue damage, we studied the effect of IL-17 blockade with a specific antibody (anti-IL-17). We found activation of Th17 cells and downregulation of forkhead box P3 mRNA in peri