Age-related increase in phorbol myristate acetate-induced lymphocyte adhesion to vascular endothelium

Lymphocyte adhesion to vascular endothelium is an important part of immune function. This investigation sought to detect differences between the adhesion of lymphocytes from young and aged human donors to vascular endothelium with and without treatment of the lymphocytes with phorbol myristate acetate (PMA), an activator of protein kinase C (PKC) that stimulates this adhesive process. T-lymphocytes were isolated from young and aged donors and adhesion assays were conducted with human umbilical vein endothelial cells (HUVEC). In some cases the HUVEC were activated by pre-incubation with tumor necrosis factor, a cytokine that increases their adhesiveness, before the addition of lymphocytes in the presence or absence of PMA. The results show that, in the basal state, lymphocytes from young and aged donors had similar levels of adherence, while with PMA activation, lymphocytes from aged donors had a significantly higher level of adherence to both activated and non-activated HUVEC. No cytotoxic effect on the HUVEC was detected. These results suggest a role for lymphocytes in diseases that predominantly affect the elderly and that are thought to involve interaction between lymphocytes and endothelium. In addition, these results indicate that there may be a change in PKC function in lymphocytes with aging.