Project description:Immunosurveillance of secondary lymphoid organs (SLO) is performed by central memory T cells that recirculate through blood. Resident memory T cells (TRM) remain parked in nonlymphoid tissues and often stably express CD69. We recently identified TRM within SLO, and this study addresses knowledge gaps in their origin and phenotype. Parabiosis of ‘dirty’ mice revealed that CD69 expression is insufficient to infer stable residence. Using selective depletion strategies, parabiosis, imaging, tissue grafting, and photoactivatable T cells, we report that restimulation of TRM within the skin or mucosa results in a substantial increase in TRM that patrol all regions of draining lymph nodes. SLO TRM were derived from nonlymphoid tissue residents. Transcriptional profiling and flow cytometry revealed a refined phenotype shared between both nonlymphoid and SLO TRM. These data demonstrate the nonlymphoid origin of SLO TRM and suggest vaccination strategies by which memory CD8 T cell immunosurveillance can be regionalized to specific lymph nodes.
Project description:Using two different experimental approaches, we here highlight the long-term residence of a substantial proportion of CD4 Treg and CD4 Tmem cells within the secondary lymphoid organs of specific pathogen-free mice. Microbiota plays an important role in T-cell residence in Peyer’s patches, but only a minor one, if any, in lymph nodes. Lymph node-resident CD4 Treg and CD4 Tmem cells share many phenotypic and functional characteristics, including a core transcriptional profile, with their cell-counterparts from non-lymphoid tissues. In particular, S1PR1 down-regulation may represent the main mechanism accounting for T-cell residency within secondary lymphoid organs. Strikingly, T-cell residence increases with age, to the point that the majority of CD4 Treg and Tmem cells from lymph nodes are in fact, resident T cells in old mice. Altogether, our results show that T-cell residence is not only a hallmark of non-lymphoid tissues, but can be extended to secondary lymphoid organs.
Project description:Recent studies have highlighted the role of sub-clones in tumors. Lymph nodes are generally the first location of metastasis for most solid epithelial tumors including Colorectal cancer (CRC). We sought to understand the genetic origin of lymph node metastasis in CRC by evaluating the relationship between CRC tumor sub-clones and lymph nodes.
Project description:The comprehensive characterization and quantification of the HIV tissue reservoirs is required to design appropriate therapeutic intervention(s) to achieve a cure. While pioneering studies demonstrated that HIV replication and spreading mainly occur in lymphoid tissues, the identification of specific cell subsets harboring replication competent virus in lymphoid tissues has long been neglected. In this context, we and others have recently shown that gut memory CD4 T cells, lymph node T follicular helper (Tfh) cells and tissue macrophages represent major HIV/SIV tissue reservoirs. Notably, Tfh cell differentiation is a multi-stage process that requires long-lasting interactions with lymph node (LN) dendritic cells (DCs) and pre-germinal center B cells in a specific cytokine/chemokine microenvironment. Lymph node DCs are endowed with an exceptional T-cell stimulatory potential and can either migrate from the periphery to the draining lymph node (migratory DCs) or locate in the LN for their entire life span (resident DCs). On the basis of these unique properties, long-term persistence of LN DCs infected with replication competent virus may represent the initial trigger of viral rebound post ART interruption and may therefore represent a major obstacle to HIV cure. We demonstrate that LN migratory DCs are infected with replication competent virus and persist despite suppressive ART. In addition, we identified the mechanisms associated with i) LN DC susceptibility to HIV infection and ii) long term persistence of HIV-infected LN DCs i.e. proliferation of infected cells in tissue sanctuaries.
Project description:Despite their key role in immunity our understanding of primary and secondary lymphoid stromal cell heterogeneity and ontogeny remains limited. Here, using genome-wide expression profiling and phenotypic and localization studies, we identify a functionally distinct subset of BP3-PDPN+PDGFRβ+/α+CD34+ stromal adventitial cells in both lymph nodes and thymus that is located within the perivascular niche surrounding PDPN-PDGFRβ+/α-Esam-1+ITGA7+ pericytes. In re-aggregate organ grafts adult CD34+ adventitial cells gave rise to multiple thymic and lymph node mesenchymal subsets including pericytes, FRC-, MRC- and FDC-like cells, the development of which was lymphoid environment dependent. During thymic ontogeny pericytes developed from a transient population of BP3-PDPN+PDGFRβ+/α+CD34-/lo anlage-seeding progenitors that subsequently up-regulated CD34 and we provide evidence suggesting that similar embryonic progenitors give rise to lymph node mesenchymal subsets. These findings extend the current understanding of lymphoid mesenchymal cell heterogeneity and highlight a role of the CD34+ vascular adventitia as a potential ubiquitous source of lymphoid stromal precursors in postnatal tissues. To comprehensively study the differences and similarities between mesenchymal stromal subsets in the thymus and lymph nodes, global gene expression analysis was performed on sorted PDPN-, BP-3-PDPN+ and BP-3+PDPN+ PDGFRb+ lymph node mesenchymal cells (LNMC) as well as PDPN- and BP-3-PDPN+ PDGFRb+ thymic mesenchymal cells (TMC) from 2 w old mice by microarray.
Project description:Despite their key role in immunity our understanding of primary and secondary lymphoid stromal cell heterogeneity and ontogeny remains limited. Here, using genome-wide expression profiling and phenotypic and localization studies, we identify a functionally distinct subset of BP3-PDPN+PDGFRβ+/α+CD34+ stromal adventitial cells in both lymph nodes and thymus that is located within the perivascular niche surrounding PDPN-PDGFRβ+/α-Esam-1+ITGA7+ pericytes. In re-aggregate organ grafts adult CD34+ adventitial cells gave rise to multiple thymic and lymph node mesenchymal subsets including pericytes, FRC-, MRC- and FDC-like cells, the development of which was lymphoid environment dependent. During thymic ontogeny pericytes developed from a transient population of BP3-PDPN+PDGFRβ+/α+CD34-/lo anlage-seeding progenitors that subsequently up-regulated CD34 and we provide evidence suggesting that similar embryonic progenitors give rise to lymph node mesenchymal subsets. These findings extend the current understanding of lymphoid mesenchymal cell heterogeneity and highlight a role of the CD34+ vascular adventitia as a potential ubiquitous source of lymphoid stromal precursors in postnatal tissues. To comprehensively study the differences and similarities between mesenchymal stromal subsets in the thymus and lymph nodes, global gene expression analysis was performed on sorted PDPN-, BP-3-PDPN+ and BP-3+PDPN+ PDGFRb+ lymph node mesenchymal cells (LNMC) as well as PDPN- and BP-3-PDPN+ PDGFRb+ thymic mesenchymal cells (TMC) from 2 w old mice by microarray. Total RNA was prepared from TMC and LNMC (pooled inguinal, brachial and axillary LN) subsets sorted from 3 (TMC) and 10-11 (LNMC) 2 weeks old mice per experiment. Isolated RNA from 3 individual experiments was amplified and prepared for hybridization to the Affymetrix Mouse Gene 1.1 ST Array at a genomics core facility: Center of Excellence for Fluorescent Bioanalytics (KFB, University of Regensburg, Germany)
Project description:Lymphatic endothelial cells (LEC) residing in lymph nodes (LN) have been shown to express genes normally restricted to one or a few tissues, termed peripheral tissue antigens (PTA). The expression of one of these PTA, tyrosinase, by LN-resident LEC has been shown to mediate peripheral T cell tolerance. We used a microarray approach to determine the gene expression profile of LN-resident LEC and blood endothelial cells as a comparison with the objective of determining the global PTA repertoire in these LN stromal populations. Skin draining and mesenteric lymph nodes were pooled from 6 week old adult C57BL/6 mice, minced, and enzymatically digested yielding single cell suspensions. Lymph node stromal cells were purified via CD45 magnetic bead negative selection and pure populations of lymphatic endothelial cells (LEC) and blood endothelial cells (BEC) were obtained via electronic cell sorting according to their expression of gp38 and CD31 (LEC: gp38+ CD31+, BEC: gp38- CD31+). Total RNA was extracted, amplified, and hybridized to Affymetrix microarrays. 3 paired independent samples of purified lymph node LEC and BEC were analyzed.
Project description:CCR6+ innate lymphoid cells were sorted from the mesenteric lymph node of naïve C57BL/6 mice Cells were sort purified as lineage negative, CD127+ CD90.2+ CCR6+ ST2-
Project description:This study examines the gene expression profiles of resident lymph node B cell populations in HIV-infected and uninfected controls.