Differential composition of lymphocyte subpopulations and activation between the hypertensive Bph/2 and normotensive Bpn/3 mouse strains.

Abstract

INTRODUCTION: Numerous studies point to a role for the immune system in various animal models of hypertension. However, little is known about the immune system of Bph/2 mice, a spontaneously hypertensive strain. METHOD: To address this, we conducted a comprehensive comparison of immune cell composition and response to polyclonal T cell activation in hypertensive Bph/2 mice and normotensive Bpn/3 control mice. We quantified immune cell populations by flow cytometry from spleen and inguinal, brachial and mesenteric lymph nodes. RESULTS: While composition of myeloid immune cell types was largely comparable between strains, we observed differences in B and T cell subpopulations. Specifically, we found an increased percentage of IgM+ IgDand IgM+ IgD- B cells in Bph/2 mice, suggesting greater baseline B cell activation or differences in B cell lineage. In addition, we observed a decreased percentage of CD4 effector memory T cells and CD8 central memory T cells. The diminished proportion of memory T cells in Bph/2 mice correlated with decreased proliferation and cytokine response of splenic T cells to polyclonal T cell activation. In splenic T cells from Bph/2 mice 24 h after activation, we observed a pronounced decrease in the majority of T cell cytokines. At 120 h after activation, the Th1 and Th17 cytokine responses of splenic T cells from Bph/2 mice were decreased, but other T cell cytokines were largely comparable between genotypes. CONCLUSION/DISCUSSION: Overall, the data suggest a decreased percentage of memory T cells in Bph/2 mice that correlates with markedly diminished proliferation and cytokine response to polyclonal activation.