InVivoMAb anti-rat Kappa Immunoglobulin Light Chain
Product Details
The MAR 18.5 monoclonal antibody reacts with the kappa chain of the rat immunoglobulin light chain. The Īŗ chain is one of two types of polypeptide subunits which make up the immunoglobulin light chain. A typical antibody is composed of two immunoglobulin heavy chains and two immunoglobulin light chains. The Īŗ chain is coded for by V (variable), J (joining) and C (constant) genes. These genes undergo V(D)J recombination to generate a diverse repertoire of immunoglobulins. This antibody is used in combination with rat anti-mouse CD19 and CD22 (clones 1D3 and CĪ³34.1) to deplete B cells in vivo.Specifications
| Isotype | Mouse IgG2a,Ā Īŗ |
|---|---|
| Recommended Isotype Control(s) | InVivoMAb mouse IgG2a isotype control, unknown specificity |
| Recommended Dilution Buffer | InVivoPure pH 7.0 Dilution Buffer |
| Conjugation | This product is unconjugated. Conjugation is available via our Antibody Conjugation Services. |
| Immunogen | Soluble rat immunoglobulin |
| Reported Applications | in vivo B cell depletion in combination with anti-CD19 (clone 1D3) and anti-CD22 (clone Cy34.1) |
| Formulation |
PBS, pH 7.0 Contains no stabilizers or preservatives |
| Endotoxin |
<2EU/mg (<0.002EU/Ī¼g) Determined by LAL gel clotting assay |
| Purity |
>95% Determined by SDS-PAGE |
| Sterility | 0.2 Āµm filtration |
| Production | Purified from cell culture supernatant in an animal-free facility |
| Purification | Protein G |
| RRID | AB_10951292 |
| Molecular Weight | 150 kDa |
| Storage | The antibody solution should be stored at the stock concentration at 4Ā°C. Do not freeze. |
Recommended Products
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Recommended Isotype Control(s)
InVivoMAb mouse IgG2a isotype control, unknown specificity
-
Recommended Dilution Buffer
InVivoPure pH 7.0 Dilution Buffer
in vivo B cell depletion in combination with anti-CD19 (clone 1D3) and anti-CD22 (clone Cy34.1)
Sawen, P., et al. (2016). "Mitotic History Reveals Distinct Stem Cell Populations and Their Contributions to Hematopoiesis" Cell Rep 14(12): 2809-2818. PubMed
Homeostasis of short-lived blood cells is dependent on rapid proliferation of immature precursors. Using a conditional histone 2B-mCherry-labeling mouse model, we characterize hematopoietic stem cell (HSC) and progenitor proliferation dynamics in steady state and following several types of induced stress. HSC proliferation following HSC transplantation into lethally irradiated mice is fundamentally different not only from native hematopoiesis but also from other stress contexts. Whereas transplantation promoted sustained, long-term proliferation of HSCs, both cytokine-induced mobilization and acute depletion of selected blood cell lineages elicited very limited recruitment of HSCs to the proliferative pool. By coupling mCherry-based analysis of proliferation history with multiplex gene expression analyses on single cells, we have found that HSCs can be stratified into four distinct subtypes. These subtypes have distinct molecular signatures and differ significantly in their reconstitution potentials, showcasing the power of tracking proliferation history when resolving functional heterogeneity of HSCs.
- Cancer Research,
- Immunology and Microbiology
A CXCR4 partial agonist improves immunotherapy by targeting polymorphonuclear myeloid-derived suppressor cells and cancer-driven granulopoiesis
Preprint on BioRxiv : the Preprint Server for Biology on 11 October 2024 by Qian, J., Ma, C., et al.
Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) are pathologically activated neutrophils that potently impair immunotherapy responses. The chemokine receptor CXCR4, a central regulator of hematopoiesis, represents an attractive PMN-MDSC target1. Here, we fused a secreted CXCR4 partial agonist TFF2 to mouse serum albumin (MSA) and demonstrated that TFF2-MSA peptide synergized with anti-PD-1 to induce tumor regression or eradication, inhibited distant metastases, and prolonged survival in multiple gastric cancer (GC) models. Using histidine decarboxylase (Hdc)-GFP transgenic mice to track PMN-MDSC in vivo , we found TFF2-MSA selectively reduced the immunosuppressive Hdc-GFP + CXCR4 hi tumor PMN-MDSCs while preserving proinflammatory neutrophils, thereby boosting CD8 + T cell-mediated anti-tumor response together with anti-PD-1. Furthermore, TFF2-MSA systemically reduced PMN-MDSCs and bone marrow granulopoiesis. In contrast, CXCR4 antagonism plus anti-PD-1 failed to provide a similar therapeutic benefit. In GC patients, expanded PMN-MDSCs containing a prominent CXCR4 + LOX-1 + subset are inversely correlated with the TFF2 level and CD8 + T cells in circulation. Collectively, our studies introduce a strategy of using CXCR4 partial agonism to restore anti-PD-1 sensitivity in GC by targeting PMN-MDSCs and granulopoiesis.
- Immunology and Microbiology
Neutrophil and macrophage crosstalk might be a potential target for liver regeneration.
In FEBS Open Bio on 1 June 2024 by Chen, Y., Yang, Y., et al.
The regenerative capability of the liver is remarkable, but further research is required to understand the role that neutrophils play in this process. In the present study, we reanalyzed single-cell RNA sequencing data from a mouse partial hepatectomy (PH) model to track the transcriptional changes in hepatocytes and non-parenchymal cells. Notably, we unraveled the regenerative capacity of hepatocytes at diverse temporal points after PH, unveiling the contributions of three distinct zones in the liver regeneration process. In addition, we observed that the depletion of neutrophils reduced the survival and liver volume after PH, confirming the important role of neutrophils in liver regeneration. CellChat analysis revealed an intricate crosstalk between neutrophils and macrophages promoting liver regeneration and, using weighted gene correlation network analysis, we identified the most significant genetic module associated with liver regeneration. Our study found that hepatocytes in the periportal zone of the liver are more active than in other zones, suggesting that the crosstalk between neutrophils and macrophages might be a potential target for liver regeneration treatment. Ā© 2024 The Authors. FEBS Open Bio published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.
- Cardiovascular biology
Stroke and myocardial infarction induce neutrophil extracellular trap release disrupting lymphoid organ structure and immunoglobulin secretion.
In Nat Cardiovasc Res on 1 May 2024 by Tuz, A. A., Ghosh, S., et al.
Post-injury dysfunction of humoral immunity accounts for infections and poor outcomes in cardiovascular diseases. Among immunoglobulins (Ig), IgA, the most abundant mucosal antibody, is produced by plasma B cells in intestinal Peyer's patches (PP) and lamina propria. Here we show that patients with stroke and myocardial ischemia (MI) had strongly reduced IgA blood levels. This was phenocopied in experimental mouse models where decreased plasma and fecal IgA were accompanied by rapid loss of IgA-producing plasma cells in PP and lamina propria. Reduced plasma IgG was detectable in patients and experimental mice 3-10ād after injury. Stroke/MI triggered the release of neutrophil extracellular traps (NETs). Depletion of neutrophils, NET degradation or blockade of NET release inhibited the loss of IgA+ cells and circulating IgA in experimental stroke and MI and in patients with stroke. Our results unveil how tissue-injury-triggered systemic NET release disrupts physiological Ig secretion and how this can be inhibited in patients. Ā© 2024. The Author(s).
- Cancer Research
The Efficacy of Nanoparticle Delivery to Hypoxic Solid Tumors by ciRGD Co-Administration Depends on Neuropilin-1 and Neutrophil Levels.
In Advanced Healthcare Materials on 1 September 2023 by Izci, M., Maksoudian, C., et al.
PubMed
The ability to improve nanoparticle delivery to solid tumors is an actively studied domain, where various mechanisms are looked into. In previous work, the authors have looked into nanoparticle size, tumor vessel normalization, and disintegration, and here it is aimed to continue this work by performing an in-depth mechanistic study on the use of ciRGD peptide co-administration. Using a multiparametric approach, it is observed that ciRGD can improve nanoparticle delivery to the tumor itself, but also to tumor cells specifically better than vessel normalization strategies. The effect depends on the level of tumor perfusion, hypoxia, neutrophil levels, and vessel permeability. This work shows that upon characterizing tumors for these parameters, conditions can be selected that can optimally benefit from ciRGD co-administration as a means to improve NP delivery to solid tumors. Ā© 2023 Wiley-VCH GmbH.
- Immunology and Microbiology
Cholesterol sulfate limits neutrophil recruitment and gut inflammation during mucosal injury.
In Frontiers in Immunology on 4 April 2023 by Morino, K., Kunimura, K., et al.
PubMed
During mucosal injury, intestinal immune cells play a crucial role in eliminating invading bacteria. However, as the excessive accumulation of immune cells promotes inflammation and delays tissue repair, it is essential to identify the mechanism that limits the infiltration of immune cells to the mucosal-luminal interface. Cholesterol sulfate (CS) is the lipid product of the sulfotransferase SULT2B1 and suppresses immune reactions by inhibiting DOCK2-mediated Rac activation. In this study, we aimed to elucidate the physiological role of CS in the intestinal tract. We found that, in the small intestine and colon, CS is predominantly produced in the epithelial cells close to the lumen. While dextran sodium sulfate (DSS)-induced colitis was exacerbated in Sult2b1-deficient mice with increased prevalence of neutrophils, the elimination of either neutrophils or intestinal bacteria in Sult2b1-deficient mice attenuated disease development. Similar results were obtained when the Dock2 was genetically deleted in Sult2b1-deficient mice. In addition, we also show that indomethacin-induced ulcer formation in the small intestine was exacerbated in Sult2b1-deficient mice and was ameliorated by CS administration. Thus, our results uncover that CS acts on inflammatory neutrophils, and prevents excessive gut inflammation by inhibiting the Rac activator DOCK2. The administration of CS may be a novel therapeutic strategy for inflammatory bowel disease and non-steroidal anti-inflammatory drug-induced ulcers. Copyright Ā© 2023 Morino, Kunimura, Sugiura, Izumi, Matsubara, Akiyoshi, Maeda, Hirotani, Sakata, Mizuno, Takahashi, Bamba, Uruno and Fukui.
- Cancer Research
Tumour Extracellular Vesicles Induce Neutrophil Extracellular Traps To Promote Lymph Node Metastasis
Preprint on BioRxiv : the Preprint Server for Biology on 14 March 2023 by Su, X., Brassard, A., et al.
PubMed
Lymph nodes (LNs) are frequently the first sites of metastasis. Currently, the only prognostic LN assessment is determining metastasis status. However, there is evidence suggesting that LN metastasis is facilitated by a pre-metastatic niche induced by tumour derived extracellular vehicles (EVs). Therefore, it is important to detect and modify the LN environmental changes. We have previously reported that neutrophil extracellular traps (NETs) can sequester and promote distant metastasis. Here, we first confirmed that LN NETs are associated with reduced patient survival. Next, we demonstrated that NETs deposition precedes LN metastasis and NETs inhibition abolishes LN metastases in animal mode. Furthermore, we discovered that EVs are essential to the formation of LN NETs. Lymphatic endothelial cells secrete CXCL8/2 in response to EVs inducing NETs formation and the promotion of LN metastasis. Our findings are the first to reveal the role of EV induced NETs in LN metastasis and provide potential immunotherapeutic vulnerabilities. Graphic Abstract Illustrative demonstration of the LNs premetastatic niche formation induced by EVs and NETs. Primary tumour constantly secretes EVs, which were actively uptaken by LECs. LECs subsequently secretes CXCL8 or CXCL2 upon EV reception. CXCL8 and CXCL2 are both neutrophil chemoattractants and potent NETs inducers. The following neutrophil recruitment and NETs formation lead to increased LN metastasis burden.
- FC/FACS,
- Cancer Research,
- Immunology and Microbiology,
- Neuroscience
GZMKhigh CD8+ T effector memory cells are associated with CD15high neutrophil abundance in non-metastatic colorectal tumors and predict poor clinical outcome.
In Nature Communications on 8 November 2022 by Tiberti, S., Catozzi, C., et al.
PubMed
CD8+ T cells are a major prognostic determinant in solid tumors, including colorectal cancer (CRC). However, understanding how the interplay between different immune cells impacts on clinical outcome is still in its infancy. Here, we describe that the interaction of tumor infiltrating neutrophils expressing high levels of CD15 with CD8+ T effector memory cells (TEM) correlates with tumor progression. Mechanistically, stromal cell-derived factor-1 (CXCL12/SDF-1) promotes the retention of neutrophils within tumors, increasing the crosstalk with CD8+ T cells. As a consequence of the contact-mediated interaction with neutrophils, CD8+ T cells are skewed to produce high levels of GZMK, which in turn decreases E-cadherin on the intestinal epithelium and favors tumor progression. Overall, our results highlight the emergence of GZMKhigh CD8+ TEM in non-metastatic CRC tumors as a hallmark driven by the interaction with neutrophils, which could implement current patient stratification and be targeted by novel therapeutics. Ā© 2022. The Author(s).
- Immunology and Microbiology
GPR55 in B cells limits atherosclerosis development and regulates plasma cell maturation.
In Nat Cardiovasc Res on 1 November 2022 by Guillamat-Prats, R., Hering, D., et al.
PubMed
Dissecting the pathways regulating the adaptive immune response in atherosclerosis is of particular therapeutic interest. Here we report that the lipid G-protein coupled receptor GPR55 is highly expressed by splenic plasma cells (PC), upregulated in mouse spleens during atherogenesis and human unstable or ruptured compared to stable plaques. Gpr55-deficient mice developed larger atherosclerotic plaques with increased necrotic core size compared to their corresponding controls. Lack of GPR55 hyperactivated B cells, disturbed PC maturation and resulted in immunoglobulin (Ig)G overproduction. B cell-specific Gpr55 depletion or adoptive transfer of Gpr55-deficient B cells was sufficient to promote plaque development and elevated IgG titers. In vitro, the endogenous GPR55 ligand lysophsophatidylinositol (LPI) enhanced PC proliferation, whereas GPR55 antagonism blocked PC maturation and increased their mitochondrial content. Collectively, these discoveries provide previously undefined evidence for GPR55 in B cells as a key modulator of the adaptive immune response in atherosclerosis.
- Neuroscience
The alarmin interleukin-1Ī± triggers secondary degeneration through reactive astrocytes and endothelium after spinal cord injury.
In Nature Communications on 2 October 2022 by Bretheau, F., Castellanos-Molina, A., et al.
PubMed
Spinal cord injury (SCI) triggers neuroinflammation, and subsequently secondary degeneration and oligodendrocyte (OL) death. We report that the alarmin interleukin (IL)-1Ī± is produced by damaged microglia after SCI. Intra-cisterna magna injection of IL-1Ī± in mice rapidly induces neutrophil infiltration and OL death throughout the spinal cord, mimicking the injury cascade seen in SCI sites. These effects are abolished through co-treatment with the IL-1R1 antagonist anakinra, as well as in IL-1R1-knockout mice which demonstrate enhanced locomotor recovery after SCI. Conditional restoration of IL-1R1 expression in astrocytes or endothelial cells (ECs), but not in OLs or microglia, restores IL-1Ī±-induced effects, while astrocyte- or EC-specific Il1r1 deletion reduces OL loss. Conditioned medium derived from IL-1Ī±-stimulated astrocytes results in toxicity for OLs; further, IL-1Ī±-stimulated astrocytes generate reactive oxygen species (ROS), and blocking ROS production in IL-1Ī±-treated or SCI mice prevented OL loss. Thus, after SCI, microglia release IL-1Ī±, inducing astrocyte- and EC-mediated OL degeneration. Ā© 2022. The Author(s).
Structural differences in bacterial lipopolysaccharides determine atherosclerotic plaque progression by regulating the accumulation of neutrophils.
In Atherosclerosis on 1 October 2022 by Saito, Y., Yamashita, T., et al.
Gut microbial lipopolysaccharide (LPS) induces endotoxemia, an independent risk factor for cardiovascular disease (CVD). However, no studies have demonstrated how structural differences in each bacterial LPS contribute to endotoxemia. Here, we investigated the effects of different acyl chains in the lipid A moiety of LPS on endotoxemia and the subsequent immune response and atherosclerotic plaque formation. Apoe-/- mice were intraperitoneally administered 2Ā mg/kg of Escherichia coli-derived LPS (E. LPS, as a representative of hexa-acylated lipid A), Bacteroides-derived LPS (B. LPS, as a representative of penta- or tetra-acylated lipid A), or saline (control) once a week, six times. An immunohistological assessment was performed on plaque sections. E. LPS administration induced endotoxemia, but B. LPS and saline did not. In E. LPS-treated mice, total plaque areas in the aortic root were significantly increased, and neutrophil accumulation and increased formation of neutrophil extracellular traps (NETs) were observed at the plaque lesions, but not in B. LPS-treated mice. A single dose of E. LPS significantly increased the accumulation of neutrophils in plaque lesions on day 3, and NET formation on day 7. E. LPS also increased interleukin-1 beta (IL-1Ī²) production in plaque lesions on day 7. Furthermore, NET formation and IL-1Ī² production were also observed in human coronary plaques. We identified a previously unknown link between structural differences in LPS and atherosclerosis. Lowering microbial LPS activity may reduce NET formation in plaques and prevent CVD progression. Copyright Ā© 2022 Elsevier B.V. All rights reserved.
- Cancer Research
Immuno-genomic profiling of biopsy specimens predicts neoadjuvant chemotherapy response in esophageal squamous cell carcinoma.
In Cell Reports Medicine on 16 August 2022 by Sasagawa, S., Kato, H., et al.
PubMed
Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive cancers and is primarily treated with platinum-based neoadjuvant chemotherapy (NAC). Some ESCCs respond well to NAC. However, biomarkers to predict NAC sensitivity and their response mechanism in ESCC remain unclear. We perform whole-genome sequencing and RNA sequencing analysis of 141 ESCC biopsy specimens before NAC treatment to generate a machine-learning-based diagnostic model to predict NAC reactivity in ESCC and analyzed the association between immunogenomic features and NAC response. Neutrophil infiltration may play an important role in ESCC response to NAC. We also demonstrate that specific copy-number alterations and copy-number signatures in the ESCC genome are significantly associated with NAC response. The interactions between the tumor genome and immune features of ESCC are likely to be a good indicator of therapeutic capability and a therapeutic target for ESCC, and machine learning prediction for NAC response is useful. Copyright Ā© 2022 The Authors. Published by Elsevier Inc. All rights reserved.
- Mycoplasmoides pneumoniae (Mycoplasma pneumoniae),
- Immunology and Microbiology
Vaccination with Mycoplasma pneumoniae membrane lipoproteins induces IL-17A driven neutrophilia that mediates Vaccine-Enhanced Disease.
In NPJ Vaccines on 29 July 2022 by Mara, A. B., Gavitt, T. D., et al.
PubMed
Bacterial lipoproteins are an often-underappreciated class of microbe-associated molecular patterns with potent immunomodulatory activity. We previously reported that vaccination of BALB/c mice with Mycoplasma pneumoniae (Mp) lipid-associated membrane proteins (LAMPs) resulted in lipoprotein-dependent vaccine enhanced disease after challenge with virulent Mp, though the immune responses underpinning this phenomenon remain poorly understood. Herein, we report that lipoprotein-induced VED in a mouse model is associated with elevated inflammatory cytokines TNF-Ī±, IL-1Ī², IL-6, IL-17A, and KC in lung lavage fluid and with suppurative pneumonia marked by exuberant neutrophilia in the pulmonary parenchyma. Whole-lung-digest flow cytometry and RNAScope analysis identified multiple cellular sources for IL-17A, and the numbers of IL-17A producing cells were increased in LAMPs-vaccinated/Mp-challenged animals compared to controls. Specific IL-17A or neutrophil depletion reduced disease severity in our VED model-indicating that Mp lipoproteins induce VED in an IL-17A-dependent manner and through exuberant neutrophil recruitment. IL-17A neutralization reduced levels of TNF-Ī±, IL-1Ī², IL-6, and KC, indicating that IL-17A preceded other inflammatory cytokines. Surprisingly, we found that IL-17A neutralization impaired bacterial clearance, while neutrophil depletion improved it-indicating that, while IL-17A appears to confer both maladaptive and protective responses, neutrophils play an entirely maladaptive role in VED. Given that lipoproteins are found in virtually all bacteria, the potential for lipoprotein-mediated maladaptive inflammatory responses should be taken into consideration when developing vaccines against bacterial pathogens. Ā© 2022. The Author(s).
- Cardiovascular biology
Neutrophils incite and macrophages avert electrical storm after myocardial infarction.
In Nat Cardiovasc Res on 1 July 2022 by Grune, J., Lewis, A. J. M., et al.
PubMed
Sudden cardiac death, arising from abnormal electrical conduction, occurs frequently in patients with coronary heart disease. Myocardial ischemia simultaneously induces arrhythmia and massive myocardial leukocyte changes. In this study, we optimized a mouse model in which hypokalemia combined with myocardial infarction triggered spontaneous ventricular tachycardia in ambulatory mice, and we showed that major leukocyte subsets have opposing effects on cardiac conduction. Neutrophils increased ventricular tachycardia via lipocalin-2 in mice, whereas neutrophilia associated with ventricular tachycardia in patients. In contrast, macrophages protected against arrhythmia. Depleting recruited macrophages in Ccr2 -/- mice or all macrophage subsets with Csf1 receptor inhibition increased both ventricular tachycardia and fibrillation. Higher arrhythmia burden and mortality in Cd36 -/- and Mertk -/- mice, viewed together with reduced mitochondrial integrity and accelerated cardiomyocyte death in the absence of macrophages, indicated that receptor-mediated phagocytosis protects against lethal electrical storm. Thus, modulation of leukocyte function provides a potential therapeutic pathway for reducing the risk of sudden cardiac death.
- Cardiovascular biology
Neutrophil extracellular traps regulate ischemic stroke brain injury.
In The Journal of Clinical Investigation on 16 May 2022 by Denorme, F., Portier, I., et al.
PubMed
Ischemic stroke prompts a strong inflammatory response, which is associated with exacerbated outcomes. In this study, we investigated mechanistic regulators of neutrophil extracellular trap (NET) formation in stroke and whether they contribute to stroke outcomes. NET-forming neutrophils were found throughout brain tissue of ischemic stroke patients, and elevated plasma NET biomarkers correlated with worse stroke outcomes. Additionally, we observed increased plasma and platelet surface-expressed high-mobility group box 1 (HMGB1) in stroke patients. Mechanistically, platelets were identified as the critical source of HMGB1 that caused NETs in the acute phase of stroke. Depletion of platelets or platelet-specific knockout of HMGB1 significantly reduced plasma HMGB1 and NET levels after stroke, and greatly improved stroke outcomes. We subsequently investigated the therapeutic potential of neonatal NET-inhibitory factor (nNIF) in stroke. Mice treated with nNIF had smaller brain infarcts, improved long-term neurological and motor function, and enhanced survival after stroke. nNIF specifically blocked NET formation without affecting neutrophil recruitment after stroke. Importantly, nNIF also improved stroke outcomes in diabetic and aged mice and was still effective when given 1 hour after stroke onset. These results support a pathological role for NETs in ischemic stroke and warrant further investigation of nNIF for stroke therapy.
- Immunology and Microbiology
GPR55 in B cells limits atherosclerosis development and regulates plasma cell maturation
Preprint on Research Square on 12 January 2022 by Guillamat-Prats, R., Hering, D., et al.
PubMed
Identifying novel pathways regulating the adaptive immune response in chronic inflammatory diseases such as atherosclerosis is of particular interest in view of developing new therapeutic drugs. Here we report that the lipid receptor GPR55 is highly expressed by splenic B cells and inversely correlates with atheroma plaque size in mice. In human carotid endarterectomy specimen, GPR55 transcript levels were significantly lower in unstable compared to stable carotid plaques. To study the impact of GPR55 deficiency in atherosclerosis, we crossed Gpr55 knockout mice with apolipoprotein E (ApoE) knockout mice and subjected the mice to Western diet for 4 to 16 weeks. Compared to ApoE-/- controls, ApoE-/-Gpr55-/- mice developed larger plaques with increased necrotic core size, associated with elevated circulating and aortic leukocyte counts. Flow cytometry, immunofluorescence and RNA-sequencing analysis of splenic B cells in these mice revealed a hyperactivated B cell phenotype with disturbed plasma cell maturation and immunoglobulin (Ig)G antibody overproduction. The specific contribution of B cell GPR55 in atherosclerosis was further studied in mixed Gpr55-/-/ĀµMT bone marrow chimeras on low density receptor deficiency (Ldlr-/-) background, revealing that B-cell specific depletion of Gpr55 was sufficient to promote plaque development. Conversely, adoptive transfer of wildtype B cells into ApoE-/-Gpr55-/- mice blunted the proatherogenic phenotype. In vitro stimulation of splenocytes with the endogenous GPR55 ligand LPI promoted plasma cell proliferation and enhanced B cell activation marker expression, which was inhibited by the GPR55 antagonist CID16020046. Collectively, these discoveries provide new evidence for GPR55 as key modulator of the adaptive immune response in atherosclerosis. Targeting GPR55 could be useful to limit inflammation and plaque progression in patients suffering from atherosclerosis.
- Immunology and Microbiology
The scaffold-dependent function of RIPK1 in dendritic cells promotes injury-induced colitis.
In Mucosal Immunology on 1 January 2022 by Moriwaki, K., Park, C., et al.
PubMed
Receptor interacting protein kinase 1 (RIPK1) is a cytosolic multidomain protein that controls cell life and death. While RIPK1 promotes cell death through its kinase activity, it also functions as a scaffold protein to promote cell survival by inhibiting FADD-caspase 8-dependent apoptosis and RIPK3-MLKL-dependent necroptosis. This pro-survival function is highlighted by excess cell death and perinatal lethality in Ripk1-/- mice. Recently, loss of function mutation of RIPK1 was found in patients with immunodeficiency and inflammatory bowel diseases. Hematopoietic stem cell transplantation restored not only immunodeficiency but also intestinal inflammatory pathology, indicating that RIPK1 in hematopoietic cells is critical to maintain intestinal immune homeostasis. Here, we generated dendritic cell (DC)-specific Ripk1-/- mice in a genetic background with loss of RIPK1 kinase activity and found that the mice developed spontaneous colonic inflammation characterized by increased neutrophil and Ly6C+ monocytes. In addition, these mice were highly resistant to injury-induced colitis. The increased colonic inflammation and the resistance to colitis were restored by dual inactivation of RIPK3 and FADD, but not by inhibition of RIPK3, MLKL, or ZBP1 alone. Altogether, these results reveal a scaffold activity-dependent role of RIPK1 in DC-mediated maintenance of colonic immune homeostasis. Ā© 2021. The Author(s).
- Immunology and Microbiology
GPR55 in B cells limits atherosclerosis development and regulates plasma cell maturation
Preprint on BioRxiv : the Preprint Server for Biology on 21 December 2021 by Guillamat-Prats, R., Hering, D., et al.
PubMed
Identifying novel pathways regulating the adaptive immune response in chronic inflammatory diseases such as atherosclerosis is of particular interest in view of developing new therapeutic drugs. Here we report that the lipid receptor GPR55 is highly expressed by splenic B cells and inversely correlates with atheroma plaque size in mice. In human carotid endarterectomy specimen, GPR55 transcript levels were significantly lower in unstable compared to stable carotid plaques. To study the impact of GPR55 deficiency in atherosclerosis, we crossed Gpr55 knockout mice with apolipoprotein E ( ApoE ) knockout mice and subjected the mice to Western diet for 4 to 16 weeks. Compared to ApoE -/- controls, ApoE -/- Gpr55 -/- mice developed larger plaques with increased necrotic core size, associated with elevated circulating and aortic leukocyte counts. Flow cytometry, immunofluorescence and RNA-sequencing analysis of splenic B cells in these mice revealed a hyperactivated B cell phenotype with disturbed plasma cell maturation and immunoglobulin (Ig)G antibody overproduction. The specific contribution of B cell GPR55 in atherosclerosis was further studied in mixed Gpr55 -/- / ĀµMT bone marrow chimeras on low density receptor deficiency ( Ldlr -/- ) background, revealing that B-cell specific depletion of Gpr55 was sufficient to promote plaque development. Conversely, adoptive transfer of wildtype B cells into ApoE -/- Gpr55 -/- mice blunted the proatherogenic phenotype. In vitro stimulation of splenocytes with the endogenous GPR55 ligand LPI promoted plasma cell proliferation and enhanced B cell activation marker expression, which was inhibited by the GPR55 antagonist CID16020046. Collectively, these discoveries provide new evidence for GPR55 as key modulator of the adaptive immune response in atherosclerosis. Targeting GPR55 could be useful to limit inflammation and plaque progression in patients suffering from atherosclerosis.
- In Vivo,
- Mus musculus (House mouse),
- Immunology and Microbiology
IL-17 mediates protective immunity against nasal infection with Bordetella pertussis by mobilizing neutrophils, especially Siglec-F+ neutrophils.
In Mucosal Immunology on 1 September 2021 by Borkner, L., Curham, L. M., et al.
PubMed
Understanding the mechanism of protective immunity in the nasal mucosae is central to the design of more effective vaccines that prevent nasal infection and transmission of Bordetella pertussis. We found significant infiltration of IL-17-secreting CD4+ tissue-resident memory T (TRM) cells and Siglec-F+ neutrophils into the nasal tissue during primary infection with B. pertussis. Il17A-/- mice had significantly higher bacterial load in the nasal mucosae, associated with significantly reduced infiltration of Siglec-F+ neutrophils. Re-infected convalescent mice rapidly cleared B. pertussis from the nasal cavity and this was associated with local expansion of IL-17-producing CD4+ TRM cells. Depletion of CD4 T cells from the nasal tissue during primary infection or after re-challenge of convalescent mice significantly delayed clearance of bacteria from the nasal mucosae. Protection was lost in Il17A-/- mice and this was associated with significantly less infiltration of Siglec-F+ neutrophils and antimicrobial peptide (AMP) production. Finally, depletion of neutrophils reduced the clearance of B. pertussis following re-challenge of convalescent mice. Our findings demonstrate that IL-17 plays a critical role in natural and acquired immunity to B. pertussis in the nasal mucosae and this effect is mediated by mobilizing neutrophils, especially Siglec-F+ neutrophils, which have high neutrophil extracellular trap (NET) activity. Ā© 2021. The Author(s).
- Cancer Research,
- Immunology and Microbiology
Gain-of-function p53R172H mutation drives accumulation of neutrophils in pancreatic tumors, promoting resistance to immunotherapy.
In Cell Reports on 24 August 2021 by Siolas, D., Vucic, E., et al.
PubMed
Tumor genotype can influence the immune microenvironment, which plays a critical role in cancer development and therapy resistance. However, the immune effects of gain-of-function Trp53 mutations have not been defined in pancreatic cancer. We compare the immune profiles generated by KrasG12D-mutated mouse pancreatic ductal epithelial cells (PDECs) engineered genetically to express the Trp53R172H mutation with their p53 wild-type control. KrasG12D/+;Trp53R172H/+ tumors have a distinct immune profile characterized by an influx of CD11b+Ly6G+ neutrophils and concomitant decreases in CD3+ TĀ cells, CD8+ TĀ cells, and CD4+ T helper 1 cells. Knockdown of CXCL2, a neutrophil chemokine, in the tumor epithelial compartment ofĀ CRISPR KrasG12D/+;Trp53R172H/+ PDEC tumors reverses the neutrophil phenotype. Neutrophil depletion of mice bearing CRISPR KrasG12D/+;Trp53R172H/+ tumors augments sensitivity to combined CD40 immunotherapy and chemotherapy. These data link Trp53R172H to the presence of intratumoral neutrophils in pancreatic cancer and suggest that tumor genotypes could inform selection of affected individuals for immunotherapy.Copyright Ā© 2021 The Authors. Published by Elsevier Inc. All rights reserved.
- Cancer Research,
- Immunology and Microbiology,
- In Vivo,
- Mus musculus (House mouse)
IL1Ī² Promotes Immune Suppression in the Tumor Microenvironment Independent of the Inflammasome and Gasdermin D.
In Cancer Immunology Research on 1 March 2021 by Kiss, M., Vande Walle, L., et al.
PubMed
IL1Ī² is a central mediator of inflammation. Secretion of IL1Ī² typically requires proteolytic maturation by the inflammasome and formation of membrane pores by gasdermin D (GSDMD). Emerging evidence suggests an important role for IL1Ī² in promoting cancer progression in patients, but the underlying mechanisms are ill-defined. Here, we have shown a key role for IL1Ī² in driving tumor progression in two distinct mouse tumor models. Notably, activation of the inflammasome, caspase-8, as well as the pore-forming proteins GSDMD and mixed lineage kinase domain-like protein in the host were dispensable for the release of intratumoral bioactive IL1Ī². Inflammasome-independent IL1Ī² release promoted systemic neutrophil expansion and fostered accumulation of T-cell-suppressive neutrophils in the tumor. Moreover, IL1Ī² was essential for neutrophil infiltration triggered by antiangiogenic therapy, thereby contributing to treatment-induced immunosuppression. Deletion of IL1Ī² allowed intratumoral accumulation of CD8+ effector T cells that subsequently activated tumor-associated macrophages. Depletion of either CD8+ T cells or macrophages abolished tumor growth inhibition in IL1Ī²-deficient mice, demonstrating a crucial role for CD8+ T-cell-macrophage cross-talk in the antitumor immune response. Overall, these results support a tumor-promoting role for IL1Ī² through establishing an immunosuppressive microenvironment and show that inflammasome activation is not essential for release of this cytokine in tumors. Ā©2020 American Association for Cancer Research.
