Regulation of CD8 T Cell Differentiation by the RNA-Binding Protein DDX5.

The RNA-binding protein DEAD-box protein 5 (DDX5) is a polyfunctional regulator of gene expression, but its role in CD8+ T cell biology has not been extensively investigated. In this study, we demonstrate that deletion of DDX5 in murine CD8+ T cells reduced the differentiation of terminal effector, effector memory T, and terminal effector memory cells while increasing the generation of central memory T cells, whereas forced expression of DDX5 elicited the opposite phenotype. DDX5-deficient CD8+ T cells exhibited increased expression of genes that promote central memory T cell differentiation, including Tcf7 and Eomes.

Clone Wars: Survival of the Fittest CD8 Trm Cells.

In this issue of Immunity, Hirai et al. illuminate competition for the cytokine TGFβ as a key regulator of CD8 tissue-resident memory T cell persistence and occupancy in the skin epidermal niche.

Heterogeneity and clonal relationships of adaptive immune cells in ulcerative colitis revealed by single-cell analyses.

Inflammatory bowel disease (IBD) encompasses a spectrum of gastrointestinal disorders driven by dysregulated immune responses against gut microbiota. We integrated single-cell RNA and antigen receptor sequencing to elucidate key components, cellular states, and clonal relationships of the peripheral and gastrointestinal mucosal immune systems in health and ulcerative colitis (UC). UC was associated with an increase in IgG1 plasma cells in colonic tissue, increased colonic regulatory T cells characterized by elevated expression of the transcription factor ZEB2, and an enrichment of a γδ T cell subset in the peripheral blood.

Early precursors and molecular determinants of tissue-resident memory CD8 T lymphocytes revealed by single-cell RNA sequencing.

During an immune response to microbial infection, CD8 T cells give rise to distinct classes of cellular progeny that coordinately mediate clearance of the pathogen and provide long-lasting protection against reinfection, including a subset of noncirculating tissue-resident memory (T) cells that mediate potent protection within nonlymphoid tissues. Here, we used single-cell RNA sequencing to examine the gene expression patterns of individual CD8 T cells in the spleen and small intestine intraepithelial lymphocyte (siIEL) compartment throughout the course of their differentiation in response to viral infection. These analyses revealed previously unknown transcriptional heterogeneity within the siIEL CD8 T cell population at several stages of differentiation, representing functionally distinct T cell subsets and a subset of T cell precursors within the tissue early in infection.

Targeting Tumor-Associated Macrophages in Cancer.

Macrophages are phagocytes that serve as a first line of defense against pathogenic insults to tissues. These innate immune cells mount proinflammatory responses to pathogens and repair damaged tissues. However, tumor-associated macrophages (TAMs) express cytokines and chemokines that can suppress antitumor immunity and promote tumor progression.

Integrin CD11b activation drives anti-tumor innate immunity.

Myeloid cells are recruited to damaged tissues where they can resolve infections and tumor growth or stimulate wound healing and tumor progression. Recruitment of these cells is regulated by integrins, a family of adhesion receptors that includes integrin CD11b. Here we report that, unexpectedly, integrin CD11b does not regulate myeloid cell recruitment to tumors but instead controls myeloid cell polarization and tumor growth.