The influence of obesity on regulatory T cell function during influenza infection

Previous work in our laboratory has demonstrated increased mortality and morbidity in influenza infected diet‐induced obese mice. Immunologically, obese mice demonstrated impaired cellular immunity, aberrant cytokine production and decreased memory T cell function. Although the mechanism for this impaired immunity remains unclear, recent research has shown that elevated leptin decreases the production of a specific subset of T cells referred to as regulatory T cells (Tregs). Tregs have been shown to suppress or enhance the immune response to viral infections; however, very little is known about the function of Tregs during an influenza infection. Therefore, Treg numbers and function were characterized in obese, hyperleptinemic mice and compared with lean mice during an influenza infection. Male, 20 week‐old, diet‐induced obese and lean mice were infected with an H1N1 strain of influenza and analyzed at several time points post infection. Flow cytometric analysis detected significant differences in Tregs resident in the lymph nodes and lungs of obese mice compared with lean controls. Obesity induced alterations in Treg numbers provides a novel mechanism in which excess adiposity impairs immunity to influenza virus. Grant Funding Source : NIH funded NORC DK 56350