Which Cutaneous T Cells Remember to Respond to Contact Allergens and Protein Antigens and How Do They Do So?

Following cutaneous exposure to viral antigens, contact allergens, or immunogenic chemicals, two populations of T cells are generated to protect against unwanted effects of these exogenous agents. The central memory T cell (T_CM) resides in lymph nodes; the resident memory T cell (T_RM) is found predominantly in the skin. These authors explored characteristics of these cell populations, which, although important to our understanding of inflammatory skin diseases, are not well defined.

In animal models, protein immunization and contact sensitization provoked T_RM development at the skin site where exposure took place and at distant skin sites. Equivalent numbers of T_CM with exactly the same T-cell receptor could be identified in draining and rem…