Corneal tissue-resident memory T cells form a unique immune compartment at the ocular surface

The eye is considered immune privileged such that immune responses are dampened to protect vision. As the most anterior compartment of the eye, the cornea is exposed to pathogens and can mount immune responses that recruit effector T cells. However, presence of immune memory in the cornea is not defined. Here, we use intravital 2-photon microscopy to examine T cell responses in the cornea in mice. We show that recruitment of CD8(+) T cells in response to ocular virus infection results in the formation of tissue-resident memory T (T-RM) cells. Motile corneal T-RM cells patrol the cornea and rapidly respond in situ to antigen rechallenge. CD103(+) T-RM cell generation requires antigen and transforming growth factor beta. In vivo imaging in humans also reveals highly motile cells that patrol the healthy cornea. Our study finds that T-RM cells form in the cornea where they can provide local protective immunity.