“A novel humanized mouse model to study the function of human cutaneous memory T cells in vivo in human skin”
Maria M. Klicznik, Ariane Benedetti, Laura M. Gail, Suraj R. Varkhande, Raimund Holly, Martin Laimer, Angelika Stoecklinger, Andreas Sir, Roland Reitsamer, Theresa Neuper, Jutta Horejs-Hoeck, Michael D. Rosenblum, Daniel J. Campbell, Eva M. Murauer & Iris K. Gratz
Abstract: 
Human skin contains a population of memory T cells that supports tissue homeostasis and provides protective immunity. The study of human memory T cells is often restricted to in vitro studies and to human PBMC serving as primary cell source. Because the tissue environment impacts the phenotype and function of memory T cells, it is crucial to study these cells within their tissue. Here we utilized immunodeficient NOD-scid IL2rγnull (NSG) mice that carried in vivo-generated engineered human skin (ES). ES was generated from human keratinocytes and fibroblasts and was initially devoid of skin-resident immune cells. Upon adoptive transfer of human PBMC, this reductionist system allowed us to study human T cell recruitment from a circulating pool of T cells into non-inflamed human skin in vivo. Circulating human memory T cells preferentially infiltrated ES and showed diverse functional profiles of T cells found in fresh human skin. The chemokine and cytokine microenvironment of ES closely resembled that of non-inflamed human skin. Upon entering the ES T cells assumed a resident memory T cell-like phenotype in the absence of infection, and a proportion of these cutaneous T cells can be locally activated upon injection of monocyte derived dendritic cells (moDCs) that presented Candida albicans. Interestingly, we found that CD69+ memory T cells produced higher levels of effector cytokines in response to Candida albicans, compared to CD69- T cells. Overall, this model has broad utility in many areas of human skin immunology research, including the study of immune-mediated skin diseases.

The open access article can be found  here.
Reviewed by Peter Steinbacher

CONGRATULATIONS!