RhoB controls the Rab11-mediated recycling and surface reappearance of LFA-1 in migrating T lymphocytes.

The regulation of cell adhesion and motility is complex and requires the intracellular trafficking of integrins to and from sites of cell adhesion, especially in fast-moving cells such as leukocytes. The Rab family of guanosine triphosphatases (GTPases) is essential for vesicle transport, and vesicles mediate intracellular integrin trafficking. We showed that RhoB regulates the vesicular transport of the integrin LFA-1 along the microtubule network in migrating T lymphocytes.

Context-Dependent Development of Lymphoid Stroma from Adult CD34(+) Adventitial Progenitors.

Despite the key role of primary and secondary lymphoid organ stroma in immunity, our understanding of the heterogeneity and ontogeny of these cells remains limited. Here, we identify a functionally distinct subset of BP3(-)PDPN(+)PDGFRβ(+)/α(+)CD34(+) stromal adventitial cells in both lymph nodes (LNs) and thymus that is located within the vascular niche surrounding PDPN(-)PDGFRβ(+)/α(-)Esam-1(+)ITGA7(+) pericytes. CD34(+) adventitial cells developed in late embryonic thymus and in postnatal LNs and in the thymus originated, along with pericytes, from a common anlage-seeding progenitor population.

Macrophage and dendritic cell subsets in IBD: ALDH+ cells are reduced in colon tissue of patients with ulcerative colitis regardless of inflammation.

Disruption of the homeostatic balance of intestinal dendritic cells (DCs) and macrophages (MQs) may contribute to inflammatory bowel disease. We characterized DC and MQ populations, including their ability to produce retinoic acid, in clinical material encompassing Crohn's ileitis, Crohn's colitis and ulcerative colitis (UC) as well as mesenteric lymph nodes (MLNs) draining these sites. Increased CD14(+)DR(int) MQs characterized inflamed intestinal mucosa while total CD141(+) or CD1c(+) DCs numbers were unchanged.

A major population of mucosal memory CD4+ T cells, coexpressing IL-18Rα and DR3, display innate lymphocyte functionality.

Mucosal tissues contain large numbers of memory CD4(+) T cells that, through T-cell receptor-dependent interactions with antigen-presenting cells, are believed to have a key role in barrier defense and maintenance of tissue integrity. Here we identify a major subset of memory CD4(+) T cells at barrier surfaces that coexpress interleukin-18 receptor alpha (IL-18Rα) and death receptor-3 (DR3), and display innate lymphocyte functionality. The cytokines IL-15 or the DR3 ligand tumor necrosis factor (TNF)-like cytokine 1A (TL1a) induced memory IL-18Rα(+)DR3(+)CD4(+) T cells to produce interferon-γ, TNF-α, IL-6, IL-5, IL-13, granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-22 in the presence of IL-12/IL-18.

CD14(hi)HLA-DR(dim) macrophages, with a resemblance to classical blood monocytes, dominate inflamed mucosa in Crohn's disease.

Intestinal M play an important role in maintaining gut homeostasis. However, little is known about these cells, their precursors, and their role in intestinal inflammation. Here, we characterize the CD14(+) mononuclear cell populations in intestinal mucosa and blood in patients with CD.