SY 17-3 ROLE OF CMV INDUCED T CELL SENESCENCE IN THE PATHOPHYSIOLOGY OF CARDIOVASCULAR DISEASE

Abstract

Abstract Immunosenescence, defined as the age-associated dysregulation and dysfunction of the immune system, is characterized by impaired protective immunity and decreased efficacy of vaccines. Immunosenescence affects both the innate and adaptive immune systems; however, the most notable changes are in T cell immunity and include thymic involution, the collapse of T cell receptor (TCR) diversity, an imbalance in T cell populations, and the clonal expansion of senescent T cells. An increasing number of immunological, clinical and epidemiological studies suggest that persistent Cytomegalovirus (CMV) infection is associated with accelerated aging of the immune system and T cell immunosenescence especially. T cell responses to CMV are restricted to a limited number of immunodominant epitopes, as compared to responses to other chronic or persistent viruses. This response results in progressive, prolonged expansion of CMV-specific T cells, termed 'memory inflation'. The expanded CMV-specific T cell population is extraordinarily large and is more prominent in the elderly. CMV-specific senescent T cells have the ability to produce large quantities of proinflammatory cytokines and cytotoxic mediators; thus, they have been implicated in the pathogenesis of many chronic inflammatory diseases. Recently, an increasing body of evidence has suggested that senescent T cells also have pathogenic potential in cardiovascular diseases, such as hypertension, heart failure, and myocardial infarction, underscoring the detrimental roles of these cells in various chronic inflammatory responses. In this presentation, we will discuss the general features of age-related alterations in T cell immunity and the possible roles of CMV induced T cell senescence in the pathophysiology of cardiovascular disease.