Azithromycin Clears Bordetella pertussis Infection in Mice but Also Modulates Innate and Adaptive Immune Responses and T Cell Memory

DAP12, an immunoreceptor tyrosine-based activation motif–bearing adapter protein, is involved in innate immunity mediated by natural killer cells and myeloid cells. We show that DAP12-deficient mouse B cells and B cells from a patient with Nasu-Hakola disease, a recessive genetic disorder resulting from loss of DAP12, showed enhanced proliferation after stimulation with anti-IgM or CpG. Myeloid-associated immunoglobulin-like receptor (MAIR) II (Cd300d) is a DAP12-associated immune receptor. Like DAP12-deficient B cells, MAIR-II–deficient B cells were hyperresponsive. Expression of a chimeric receptor composed of the MAIR-II extracellular domain directly coupled to DAP12 into the DAP12-deficient or MAIR-II–deficient B cells suppressed B cell receptor (BCR)–mediated proliferation. The chimeric MAIR-II–DAP12 receptor recruited the SH2 domain–containing protein tyrosine phosphatase 1 (SHP-1) after BCR stimulation. DAP12-deficient mice showed elevated serum antibodies against self-antigens and enhanced humoral immune responses against T cell–dependent and T cell–independent antigens. Thus, DAP12-coupled MAIR-II negatively regulates B cell–mediated adaptive immune responses.

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Antigen‐driven T‐cell repertoire selection during adaptive immune responses

Immunology and Cell Biology ◽

10.1038/icb.2010.117 ◽

2010 ◽

Vol 89 (1) ◽

pp. 54-59 ◽

Cited By ~ 13

Author(s):

Christina K Baumgartner ◽

Laurent P Malherbe

Keyword(s):

T Cell ◽

Immune Responses ◽

T Cell Repertoire ◽

Cell Repertoire ◽

Adaptive Immune Responses ◽

Adaptive Immune ◽

Repertoire Selection

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Intestinal Epithelial HIF-2 Is Protective in Gut Graft-Versus-Host-Disease

Blood ◽

10.1182/blood.v126.23.1865.1865 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1865-1865

Author(s):

Rena Feinman ◽

Iriana Colorado ◽

Keyi Wang ◽

Eugenia Dziopa ◽

Leah Dziopa ◽

...

Keyword(s):

Bone Marrow ◽

Stem Cell ◽

T Cell ◽

Immune Responses ◽

Intestinal Inflammation ◽

Intestinal Stem Cell ◽

Intestinal Epithelial ◽

Adaptive Immune Responses ◽

Graft Versus Host ◽

Adaptive Immune

Abstract The failure to control both innate and adaptive immune responses in the gut has recently been implicated as a major pathogenic mechanism in the development of graft-versus-host disease (GVHD). Reduced oxygen availability in the intestine has been causally linked to gastrointestinal disease. During intestinal inflammation, increased metabolic activity of resident and infiltrating immune cells, bacteria and reduced blood flow may lead to a sharp decrease of oxygen, resulting in "inflammatory" hypoxia. The transcription factor family, hypoxia-inducible factor (HIF) originally discovered as a master regulator of the adaptive response to hypoxia, has recently emerged as a key regulator of the innate and adaptive immune responses. The HIF heterodimer consists of an oxygen-labile α subunit (HIFα) and a constitutively expressed HIF-1β subunit. Both HIF-1α and HIF-2α expression are markedly elevated in intestinal epithelial cells of patients with inflammatory bowel disease (IBD) and intestinal epithelial HIF-1 attenuates colitis in preclinical mouse models. Although HIF-2 has not been studied extensively in intestinal inflammation, it has emerged as a key regulator in intestinal iron homeostasis. Given that IBD and GVHD share many pathogenic mechanisms, we hypothesized that a sustained HIF response will protect the host intestinal epithelium from conditioning- and alloreactive T cell-induced gut damage. To determine the functional significance of intestinal epithelial HIF-1 and HIF-2 in gut GVHD, we generated conditional intestinal epithelial HIF-1α (HIF-1αΔIE) and HIF-2αΔIE vil-cre knockout (KO) mice on a C57BL/6 (B6) background lacking HIF-1α or HIF-2α in the host intestinal epithelium. Using a fully MHC mismatched B10.BR (H2k)→B6 (H2b) bone marrow transplant (BMT) model, loss of intestinal epithelial HIF-2 reduced the median survival time (43d) compared to wild-type (WT) recipients (58d, log-rank test, P < 0.005). Although intestinal epithelial HIF-1 deficiency shortened the median survival time (48.5d), it did not reach statistical difference. Loss of intestinal epithelial HIF-1 or HIF-2 worsened GVHD-induced histopathologic crypt damage compared to WT mice transplanted with T cell depleted bone marrow (BM) and enriched T cells (BM+T), 8d post- BMT. Pronounced subepithelial lifting, mucosal edema and sloughing were more evident in the villus tips of HIF-2αΔIE mice than HIF-1αΔIE mice. Hyperplastic crypts that are characteristic of regenerating crypts after radiation-induced damage were observed in Ki67-stained ileal/jejunal sections of WT mice post-BMT whereas fewer regenerating Ki67-labeled crypts were found in both HIF-1αΔIE and HIF-2αΔIE mice. In control T cell depleted BM groups (WT, HIF-1αΔIE and HIF-2αΔIE), Ki67+ -proliferating cells resided at the crypt base. Using quantitative real-time PCR analysis, we determined whether intestinal epithelial HIF-1 and HIF-2 differentially regulated the expression of Paneth cells and intestinal stem cell markers in the jejunum, 8d post-BMT. A 5-fold and 2-fold decrease in lysozyme (Lyz) mRNA levels occurred in WT (p<0.001) and HIF-1αΔIE BM+T mice (p<0.001) compared to their respective BM groups, 8d post-BMT. However, due to a 2-fold decrease in endogenous Lyz expression in HIF-1αΔIE (p<0.01) and HIF-2αΔIE (p<0.001) BM mice compared to WT BM mice, Lyz levels were not differentially changed among BM+T groups. Loss of either intestinal epithelial HIF-1 or HIF-2 reduced Reg3γ (p<0.05) and Sox9 (p<0.01) levels whereas only epithelial HIF-1 deficiency reduced Hes-1 by 2-fold (p<0.001) and prevented the recovery of the Lgr5 levels (p<0.01) compared to WT BM+T mice. In summary, we found that both intestinal epithelial HIF-1 and HIF-2 may protect the intestinal stem cell niche from GVHD-induced injury. Importantly, our results suggest that intestinal epithelial HIF-2 may be necessary in preventing GVHD-induced mortality. Disclosures No relevant conflicts of interest to declare.

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In Vitro Platform Establishes Antigen-Specific CD8+ T Cell Cytotoxicity to Encapsulated Cells via Indirect Antigen Recognition

10.1101/2019.12.11.872978 ◽

2019 ◽

Author(s):

Ying Li ◽

Anthony W. Frei ◽

Ethan Y. Yang ◽

Irayme Labrada-Miravet ◽

Chuqiao Sun ◽

...

Keyword(s):

T Cell ◽

Immune Responses ◽

T Cell Activation ◽

Cell Activation ◽

Immune Recognition ◽

Adaptive Immune Responses ◽

Activated T Cells ◽

Encapsulated Cells ◽

Adaptive Immune

AbstractCell replacement therapy has the potential to cure diseases caused by the absence or malfunction of specialized cells. A substantial impediment to the success of any non-autologous cellular transplant is the need for systemic immunosuppressive drugs to prevent host-mediated rejection of the foreign cells. Cellular encapsulation, i.e., the entrapment of cells within stable polymeric hydrogels, has been clinically explored to prevent host immune recognition and attack, but the efficacy of these encapsulated grafts is poor. While several studies have explored improvements in innate immune acceptance of these encapsulated cells, little attention has been paid to the roles of adaptive immune responses, specifically graft-targeting T cell activation, in graft destabilization. Herein, we established an efficient, single-antigen in vitro platform capable of delineating direct and indirect host T cell recognition to microencapsulated cellular grafts and evaluating their consequential impacts. Using alginate as the model hydrogel, encapsulated membrane-bound ovalbumin (mOVA) stimulator cells were incubated with antigen-specific OTI lymphocytes and subsequent OVA-specific CD8+ T cell activation and effector function were quantified. We established that alginate microencapsulation abrogates direct T cell activation by interrupting donor-host interaction; however, indirect T cell activation mediated by host antigen presenting cells (APCs) primed with shed donor antigens still occurs. These activated T cells imparted cytotoxicity on the encapsulated cells, likely via diffusion of cytotoxic solutes. Overall, this platform delivers unique mechanistic insight into the impacts of hydrogel encapsulation on host adaptive immune responses, as well as a tool for the efficient immune screening on new encapsulation methods and/or synergistic immunomodulatory agents.

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Batf3-Dependent CD11blow/− Peripheral Dendritic Cells Are GM-CSF-Independent and Are Not Required for Th Cell Priming After Subcutaneous Immunization

Blood ◽

10.1182/blood.v118.21.1113.1113 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1113-1113

Author(s):

Brian T. Edelson ◽

Kenneth M. Murphy

Keyword(s):

Dendritic Cells ◽

T Cell ◽

Immune Responses ◽

Lymphoid Tissue ◽

Peripheral Tissue ◽

Adaptive Immune Responses ◽

Gm Csf ◽

Adaptive Immune ◽

Th Cell ◽

Subcutaneous Immunization

Abstract Abstract 1113 Granulocyte/macrophage colony stimulating factor (GM-CSF) regulates the development and activity of several myeloid cell types, including dendritic cells (DCs), thereby influencing the initiation and maintenance of adaptive immune responses. Mice lacking GM-CSF or its receptor show decreased antigen specific T cell priming against the encephalitogenic peptide of myelin oligodendrocyte glycoprotein (MOG35–55), and are resistant to experimental autoimmune encephalitis (EAE), a mouse model of multiple sclerosis. Beyond this role in priming adaptive immune responses, GM-CSF acts to sustain ongoing T cell effector responses, both in EAE initiated by MOG35–55 peptide and in other models of autoimmunity. A recent report has argued that part of the role for GM-CSF in EAE is based on its requirement for the development of a subset of dermal DCs, termed CD11blow/−Langerin+CD103+ DCs (J Exp Med. 207:953–61, 2010). These dermal DCs represent one anatomic subtype of peripheral tissue CD11blow/−CD103+ DCs, and share the properties of efficient antigen cross-presentation and IL-12 production with lymphoid tissue-resident CD8α+ DCs. Peripheral tissue CD11blow/−CD103+ DCs and lymphoid tissue-resident CD8α+ DCs are developmentally related, each being dependent on FMS-like tyrosine kinase 3 ligand (Flt3L), and requiring the transcription factors Batf3, Irf8, and Id2 for development. Mice deficient in any one of these transcription factors selectively lack these DC subsets, with Batf3−/− mice representing the best model for studying the role of these DCs in vivo, as Irf8−/− and Id2−/− mice display more widespread immune defects. Here, we directly compared the development of peripheral tissue DCs and susceptibility to EAE in GM-CSF receptor deficient (Csf2rb−/−) and Batf3−/− mice. We confirmed that Csf2rb−/− mice displayed poor priming of MOG35-55 peptide-specific T cell responses and resisted induction of EAE. Importantly, however, we found that Batf3-dependent dermal CD11blow/−Langerin+ DCs did, in fact, develop in Csf2rb−/− mice, but that these DCs expressed reduced, but not absent, levels of the surface marker CD103. In contrast, Batf3−/− mice, lacking all peripheral CD11blow/− DCs and lymphoid tissue-resident CD8α+ DCs, showed robust Th cell priming after subcutaneous immunization, and were fully susceptible to EAE. These results exclude the hypothesis that defective T effector cell priming and resistance to EAE exhibited by Csf2rb−/− mice result from the absence of dermal CD11blow/−Langerin+CD103+ DCs, and instead suggest that GM-CSF is acting via different mechanisms to promote autoimmunity. Disclosures: No relevant conflicts of interest to declare.

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