isolating-lymphocytes-from-the-mouse-small-intestinal-immune-system

Isolating Lymphocytes from the Mouse Small Intestinal Immune System

The intestinal immune system plays an essential role in maintaining the barrier function of the gastrointestinal tract by generating tolerant responses to ...

Stony Brook University

Editorial: Vγ9Vδ2 T cells: triple costimulation goes the distance.

Memory γδ T cells are important for the clearance of Listeria monocytogenes infection in the intestinal mucosa. However, the mechanisms by which memory γδ T cells provide protection against secondary oral infection are poorly understood. Here we used a recombinant strain of L. monocytogenes that efficiently invades the intestinal epithelium to show that Vγ4(+) memory γδ T cells represent a resident memory (Trm) population in the mesenteric lymph nodes (MLNs). The γδ Trm exhibited a remarkably static pattern of migration that radically changed following secondary oral L. monocytogenes infection. The γδ Trms produced IL-17A early after rechallenge and formed organized clusters with myeloid cells surrounding L. monocytogenes replication foci only after a secondary oral infection. Antibody blocking studies showed that in addition to IL-17A, the chemokine receptor C-X-C chemokine receptor 3 (CXCR3) is also important to enable the local redistribution of γδ Trm cells and myeloid cells specifically near the sites of L. monocytogenes replication within the MLN to restrict bacterial growth and spread. Our findings support a role for γδ Trms in orchestrating protective immune responses against intestinal pathogens.

IL-17A-producing resident memory γδ T cells orchestrate the innate immune response to secondary oral Listeria monocytogenes infection.

Bioactive sphingolipids are modulators of immune processes and their metabolism is often dysregulated in ulcerative colitis, a major category of inflammatory bowel disease (IBD). While multiple axes of sphingolipid metabolism have been investigated to delineate mechanisms regulating ulcerative colitis, the role of acid ceramidase (AC) in intestinal inflammation is yet to be characterized. Here we demonstrate that AC expression is elevated selectively in the inflammatory infiltrate in human and murine colitis. To probe for mechanistic insight into how AC up-regulation can impact intestinal inflammation, we investigated the selective loss of AC expression in the myeloid population. Using a model of intestinal epithelial injury, we demonstrate that myeloid AC conditional knockout mice exhibit impairment of neutrophil recruitment to the colon mucosa as a result of defective cytokine and chemokine production. Furthermore, the loss of myeloid AC protects from tumor incidence in colitis-associated cancer (CAC) and inhibits the expansion of neutrophils and granulocytic myeloid-derived suppressor cells in the tumor microenvironment. Collectively, our results demonstrate a tissue-specific role for AC in regulating neutrophilic inflammation and cytokine production. We demonstrate novel mechanisms of how granulocytes are recruited to the colon that may have therapeutic potential in intestinal inflammation, IBD, and CAC.-Espaillat, M. P., Snider, A. J., Qiu, Z., Channer, B., Coant, N., Schuchman, E. H., Kew, R. R., Sheridan, B. S., Hannun, Y. A., Obeid, L. M. Loss of acid ceramidase in myeloid cells suppresses intestinal neutrophil recruitment.

Loss of acid ceramidase in myeloid cells suppresses intestinal neutrophil recruitment.

Murine Ly6Cinflammatory monocytes (IMs) require CCR2 to leave the bone marrow and enter mesenteric lymph nodes (MLNs) and other organs in response toinfection. We are investigating how IMs, which can differentiate into CD11cdendritic cells (DCs), contribute to innate and adaptive immunity toPreviously, we obtained evidence that IMs are important for a dominant CD8T cell response to the epitope YopEand host survival using intravenous infections with attenuatedHere we challenged CCR2or CCR2mice orally with wild-typeto investigate how IMs contribute to immune responses during intestinal infection. Unexpectedly, CCR2mice did not have reduced survival but retained body weight better and their MLNs clearedfaster and with reduced lymphadenopathy compared to controls. Enhanced bacterial clearance in CCR2mice correlated with reduced numbers of IMs in spleens and increased numbers of neutrophils in livers.imaging of MLNs and spleens from CCR2-GFP mice showed that green fluorescent protein-positive (GFP) IMs accumulated at the periphery of neutrophil-richcontaining pyogranulomas. GFPIMs colocalized with CD11ccells and YopE-specific CD8T cells in MLNs, suggesting that IM-derived DCs prime adaptive responses inpyogranulomas. Consistently, CCR2mice had reduced numbers of splenic DCs, YopE-specific CD8T cells, CD4T cells, and B cells in organs and lower levels of serum antibodies toantigens. Our data suggest that IMs differentiate into DCs in MLN pyogranulomas and direct adaptive responses in T cells at the expense of innate immunity during oralinfection.

CCR2Inflammatory Monocytes Are Recruited to Yersinia pseudotuberculosis Pyogranulomas and Dictate Adaptive Responses at the Expense of Innate Immunity during Oral Infection.

Article	Year
Editorial: Vγ9Vδ2 T cells: triple costimulation goes the distance. Journal of leukocyte biology\| PubMed ID: 27034461	2016
IL-17A-producing resident memory γδ T cells orchestrate the innate immune response to secondary oral Listeria monocytogenes infection. Proceedings of the National Academy of Sciences of the United States of America\| PubMed ID: 27402748	2016
Loss of acid ceramidase in myeloid cells suppresses intestinal neutrophil recruitment. FASEB journal : official publication of the Federation of American Societies for Experimental Biology\| PubMed ID: 29259036	2018
CCR2Inflammatory Monocytes Are Recruited to Yersinia pseudotuberculosis Pyogranulomas and Dictate Adaptive Responses at the Expense of Innate Immunity during Oral Infection. Infection and immunity\| PubMed ID: 29263104	2018

Brian S. Sheridan

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