T cells in autoimmunity

A two-photon fluorescence microscopy study of rats with experimental autoimmune encephalomyelitis — a model for multiple sclerosis — shows autoimmune-disease-triggering blood T cells first directly attaching and then scanning the internal surface of the spinal meningeal vasculature, sometimes crawling against the direction of blood flow. Once across the blood–brain barrier, the T cells engage with antigen-presenting phagocytes that in turn stimulate their further differentiation and tissue infiltration. The structures involved in these interactions with T cells could be potential candidate targets for therapy against autoimmune brain disease.