Mast cells and T cells interactions at the host-environment interfaces

A balanced interplay between immune cells, commensal as well as pathogenic microbiota at host-environment interfaces such as the gut and the skin maintains homeostasis in the host. A complex network that links innate and adaptive immune responses aims to protect humans from invading pathogens and quickly resolves inflammation to reestablish homeostasis upon infection. Lack of regulation of such mechanisms can lead to chronic inflammation and immunopathology. DCs and MCs are crucial cells of the innate immune system able to orchestrate the development of adaptive immune responses. More importantly, MC-DC bidirectional interactions with both microbiota and the adaptive immunity shape the differentiation of T cell subsets into effector and memory T cells. The above discussed studies aimed at shedding light into the factors that contribute to the induction or suppression of inflammatory responses in the gut and in the skin. Understanding the molecular and cellular mechanisms that underlie the development of pro- and anti-inflammatory signatures during infections allows the design of novel strategies to counter-regulate such responses. In conclusion, these studies have dissected and have increased the understanding of important mechanisms underlying the development of immune responses, activation of immune cell subsets and interaction of immune cells at host-environment interfaces. In parallel, potential future novel and translational approaches were assessed to reduced proinflammatory responses such as the characterization and transfer of IL-10-producing T-bet-deficient Th2 cells able to suppress primary and memory CD8+ T cell responses and to prevent the development of diabetes as well as fecal transplantation experiments of bacterial species that protected recipient mice from MC-driven skin inflammation. Some of these results will be translated into novel therapies in humans in the near future.