The alarmin interleukin-33 promotes the expansion and preserves the stemness of Tcf-1 CD8 T cells in chronic viral infection.

T cell factor 1 (Tcf-1) expressing CD8 T cells exhibit stem-like self-renewing capacity, rendering them key for immune defense against chronic viral infection and cancer. Yet, the signals that promote the formation and maintenance of these stem-like CD8 T cells (CD8SL) remain poorly defined. Studying CD8 T cell differentiation in mice with chronic viral infection, we identified the alarmin interleukin-33 (IL-33) as pivotal for the expansion and stem-like functioning of CD8SL as well as for virus control.

TLR2 Signaling in Skin Nonhematopoietic Cells Induces Early Neutrophil Recruitment in Response to Leishmania major Infection.

Neutrophils are rapidly recruited to the mammalian skin in response to infection with the cutaneous Leishmania pathogen. The parasites use neutrophils to establish the disease; however, the signals driving early neutrophil recruitment are poorly known. Here, we identified the functional importance of TLR2 signaling in this process.

Perivascular Fibroblasts of the Developing Spleen Act as LTα1β2-Dependent Precursors of Both T and B Zone Organizer Cells.

T and B cell compartmentalization is a hallmark of secondary lymphoid organs and is maintained by chemokine-expressing stromal cells. How this stromal cell network initially develops and differentiates into two distinct subsets is poorly known, especially for the splenic white pulp (WP). Here, we show that perivascular fibroblast precursors are triggered by LTα1β2 signals to expand, express CCL19/21, and then differentiate into two functionally distinct fibroblast subsets responsible for B and T cell clustering and WP compartmentalization.