T cell-mediated development of stromal fibroblasts with an immune-enhancing chemokine profile

Abstract

Stromal fibroblasts reside in inflammatory tissues that are characterized by either immune suppression or immune activation, but whether these cells adapt to these contrasting microenvironments is not known. Cancer-associated fibroblasts (CAFs) mediate immune quiescence by producing the chemokine CXCL12 that coats cancer cells to suppress T cell infiltration. We examined whether CAFs can adopt an immune-promoting chemokine profile. Single-cell RNA-sequencing of CAFs from mouse pancreatic adenocarcinomas identified a sub-population with decreased expression of CXCL12 and increased expression of the T cell-attracting chemokine, CXCL9, that was expanded when tumors were infiltrated with T cells. Conditioned media from activated CD8+ T cells containing TNFα and IFNγ converted the chemokine profile of stromal fibroblasts from a CXCL12+/CXCL9- immune suppressive phenotype into a CXCL12-/CXCL9+ immune-activating phenotype. Studies with recombinant cytokines showed that TNFα acted synergistically with IFNγ to induce CXCL9 expression, and alone was mainly responsible for suppressing CXCL12 expression. This coordinated chemokine switch demonstrates that stromal fibroblasts have a phenotypic plasticity that allow their adaptation to contrasting immune tissue microenvironments.

Intratumoral NKT cell accumulation promotes antitumor immunity in pancreatic cancer

“…Freshly dissected tumors were digested with 0.2 mg/mL Collagenase P (Roche, 11213857001), 0.2 mg/mL Dispase (Gibco, 17105041), and 0.1 mg/mL DNase I (Roche, 10104159001) in RPMI-1640 containing 2% FBS as described previously ( 79 ), with the following modifications. The digestion time was decreased to 20 min twice.…”