Study of cellular immune defense & T cell subsets among apparently healthy obese subjects

Abstract

Overweight and Obesity are defined as "abnormal accumulation offat that may negatively affects health.Globally, the number of obese individuals has reached alarming proportions. According to the WHO latest estimates, about 13% of the world’s adult populations were obese and 39% were overweight in 2014. Several co morbidities are associated with this disease, especially immune dysfunction. Many studies demonstrated the negative impact of excess adiposity on immune function, provingthat changes in fat mass and the immune system are intimately linked. Studies have reported that White Adipose Tissue (WAT) is not only a storage organ, but produces close to 100 cytokines. These secreted adipokines are directly correlated to the increased adipose tissue mass and play an intricate role in various aspects of the innate and adaptive immune response and participate in a wide variety ofphysiological or physiopathological processes including food intake, insulin sensitivity and inflammation. In the obese status, secretion of these adipokinessuch as leptin and the proinflammatory cytokines like TNFα, IL-6 and IL-1β are bound to increase. When such pro inflammatory cytokines are secreted into blood, they are likely to produce disastrous condition for the host. This pro inflammatory excess energy milieu could have a definite impact on immune cell function under obesity. Such heightened pro-inflammatory cytokine expression, associated with increased tissue inflammation leading to increased mortality upon infection was seen in diet induced obesity(DIO) animals. Further, enhanced pro inflammatory cytokine expression was also associated with lower memory response in DIO animals. However, more studies are needed to delineate the mechanism by which this excess inflammatory response desensitizes the immune cells during an antigenic exposure.