Hypoxia and IL-15 Cooperate to Induce Perforin Expression by CD8 T Cells and Promote Damage to the Skin in Murine Cutaneous Leishmaniasis.

Cutaneous leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania, and although parasites influence disease severity, cytotoxic CD8 T-cell responses mediate damage to the infected skin. We found that the cytotoxic protein perforin was expressed in CD8 T cells only upon recruitment to Leishmania-infected skin, suggesting that lesional inflammatory cues induced perforin. In this study, using a mouse model of Leishmania major infection, we demonstrated that the expression of perforin was driven by a combination of hypoxia and IL-15, both of which are microenvironmental signals present within Leishmania-infected skin.

Neutrophil-mediated hypoxia drives pathogenic CD8+ T cell responses in cutaneous leishmaniasis.

Cutaneous leishmaniasis caused by Leishmania parasites exhibits a wide range of clinical manifestations. Although parasites influence disease severity, cytolytic CD8+ T cell responses mediate disease. Although these responses originate in the lymph node, we found that expression of the cytolytic effector molecule granzyme B was restricted to lesional CD8+ T cells in Leishmania-infected mice, suggesting that local cues within inflamed skin induced cytolytic function.

Pathogenic CD8 T cell responses are driven by neutrophil-mediated hypoxia in cutaneous leishmaniasis.

Cutaneous leishmaniasis caused by parasites exhibits a wide range of clinical manifestations. Although parasites influence disease severity, cytolytic CD8 T cell responses mediate disease. While these responses originate in the lymph node, we find that expression of the cytolytic effector molecule granzyme B is restricted to lesional CD8 T cells in - infected mice, suggesting that local cues within inflamed skin induce cytolytic function.