The role of central memory CD8 T cells in the kidney and the role of these cells in genesis of hypertension

Immunological memory is an important function of the adaptive immunity in response to pathogenic stimuli. Effector memory T cells, which are CD44 high CD62L low, reside in various non‐lymphoid tissues and serve as a first line defense against foreign antigens. We have previously shown that T cells are important in hypertension, but the role of memory T cells has not been defined. Here, we show that hypertension also causes immunological memory. The presences of CD8 + / CD62Lhi/CC44hi, CCR7hi central memory‐like cells in the kidney are increased 5 to 10‐fold compared to sham infused mice. Moreover, the central memory CD8 T cells produce IFN‐r and up‐regulate IL‐18R. To examine a potential role of these cells in hypertension, we re‐infused a low dose of angiotensin II that minimally raises blood pressure in naïve mice (200 ng/kg/min) 4 weeks after stopping an initial infusion of either high dose angiotensin II or vehicle. This low‐dose angiotensin II increased blood pressure to 137±6mmHg in the animals that had previously received a vehicle infusion, but to 172±12mmHg in mice that had received angiotensin II. Thus, these studies show that hypertension is associated with the development of central memory CD8 + T cells and that these cells may promote a severe hypertensive response to subsequent exposure to angiotensin II. This memory model allows us to investigate the role of memory CD8 T cells in genesis of hypertension.