[HTML][HTML] Staphylococcus epidermidis boosts innate immune response by activation of gamma delta T cells and induction of perforin-2 in human skin

I Pastar, K O'Neill, L Padula, CR Head… - Frontiers in …, 2020 - frontiersin.org
I Pastar, K O'Neill, L Padula, CR Head, JL Burgess, V Chen, D Garcia, O Stojadinovic…
Frontiers in immunology, 2020frontiersin.org
Perforin-2 (P-2) is an antimicrobial protein with unique properties to kill intracellular bacteria.
Gamma delta (GD) T cells, as the major T cell population in epithelial tissues, play a central
role in protective and pathogenic immune responses in the skin. However, the tissue-
specific mechanisms that control the innate immune response and the effector functions of
GD T cells, especially the cross-talk with commensal organisms, are not very well
understood. We hypothesized that the most prevalent skin commensal microorganism …
Perforin-2 (P-2) is an antimicrobial protein with unique properties to kill intracellular bacteria. Gamma delta (GD) T cells, as the major T cell population in epithelial tissues, play a central role in protective and pathogenic immune responses in the skin. However, the tissue-specific mechanisms that control the innate immune response and the effector functions of GD T cells, especially the cross-talk with commensal organisms, are not very well understood. We hypothesized that the most prevalent skin commensal microorganism, Staphylococcus epidermidis, may play a role in regulating GD T cell-mediated cutaneous responses. We analyzed antimicrobial protein P-2 expression in human skin at a single cell resolution using an amplified fluorescence in situ hybridization approach to detect P-2 mRNA in combination with immunophenotyping. We show that S. epidermidis activates GD T cells and upregulates P-2 in human skin ex vivo in a cell-specific manner. Furthermore, P-2 upregulation following S. epidermidis stimulation correlates with increased ability of skin cells to kill intracellular Staphylococcus aureus. Our findings are the first to reveal that skin commensal bacteria induce P-2 expression, which may be utilized beneficially to modulate host innate immune responses and protect from skin infections.
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