[In vivo imaging of cutaneous inflammation: novel insights into cutaneous immune responses revealed by multi-photon...

Skin is an outermost organ that serves as an interface between the host and the environment. The skin provides not only mechanical barrier functions, but also an active immunological barrier that provides the first line of defense against infections. For the effective clearance of pathogens or antigens in the skin, immune cells, especially effector T cells, must quickly exert their effector functions while avoiding the host damage by their excess activation. Therefore, the quality, magnitude, and the duration of the effector T cell activity must be carefully regulated. Here, we will review our recent findings on the effector T cell dynamics, dendritic cell dynamics, and the regulatory mechanisms for effector T cells activation in the skin, as revealed by the live imaging techniques using multi-photon microscopy.