1. Skin resident memory CD8+ T cells are phenotypically and functionally distinct from circulating populations and lack immediate cytotoxic function.
- Author
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Seidel, J. A., Vukmanovic‐Stejic, M., Muller‐Durovic, B., Patel, N., Fuentes‐Duculan, J., Henson, S. M., Krueger, J. G., Rustin, M. H. A., Nestle, F. O., Lacy, K. E., and Akbar, A. N.
- Subjects
T cells ,LYMPHOCYTES ,SKIN ,BODY covering (Anatomy) ,GRANZYMES - Abstract
Summary: The in‐depth understanding of skin resident memory CD8
+ T lymphocytes (TRM ) may help to uncover strategies for their manipulation during disease. We investigated isolated TRM from healthy human skin, which expressed the residence marker CD69, and compared them to circulating CD8+ T cell populations from the same donors. There were significantly increased proportions of CD8+ CD45RA– CD27– T cells in the skin that expressed low levels of killer cell lectin‐like receptor G1 (KLRG1), CD57, perforin and granzyme B. The CD8+ TRM in skin were therefore phenotypically distinct from circulating CD8+ CD45RA– CD27– T cells that expressed high levels of all these molecules. Nevertheless, the activation of CD8+ TRM with T cell receptor (TCR)/CD28 or interleukin (IL)‐2 or IL‐15 in vitro induced the expression of granzyme B. Blocking signalling through the inhibitory receptor programmed cell death 1 (PD)‐1 further boosted granzyme B expression. A unique feature of some CD8+ TRM cells was their ability to secrete high levels of tumour necrosis factor (TNF)‐α and IL‐2, a cytokine combination that was not seen frequently in circulating CD8+ T cells. The cutaneous CD8+ TRM are therefore diverse, and appear to be phenotypically and functionally distinct from circulating cells. Indeed, the surface receptors used to distinguish differentiation stages of blood T cells cannot be applied to T cells in the skin. Furthermore, the function of cutaneous TRM appears to be stringently controlled by environmental signals in situ. [ABSTRACT FROM AUTHOR]- Published
- 2018
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