scholarly journals Non‐neutralizing antibodies protect against chronic LCMV infection by promoting infection of inflammatory monocytes in mice

2021 ◽  
Author(s):  
Diana Stoycheva ◽  
Ioana Sandu ◽  
Fabienne Gräbnitz ◽  
Ana Amorim ◽  
Mariana Borsa ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Inflammatory Monocytes ◽  
Lcmv Infection

scholarly journals Inflammatory Monocytes Recruited to the Liver within 24 Hours after Virus-Induced Inflammation Resemble Kupffer Cells but Are Functionally Distinct

2015 ◽  
Vol 89 (9) ◽  
pp. 4809-4817 ◽  
Author(s):  
Dowty Movita ◽  
Martijn D. B. van de Garde ◽  
Paula Biesta ◽  
Kim Kreefft ◽  
Bart Haagmans ◽  
...  
Keyword(s):  
Immune Responses ◽  
Viral Hepatitis ◽  
Proinflammatory Cytokines ◽  
Kupffer Cells ◽  
Model Systems ◽  
Liver Inflammation ◽  
Future Treatment ◽  
Lps Challenge ◽  
Inflammatory Monocytes ◽  
Lcmv Infection

ABSTRACTDue to a scarcity of immunocompetent animal models for viral hepatitis, little is known about the early innate immune responses in the liver. In various hepatotoxic models, both pro- and anti-inflammatory activities of recruited monocytes have been described. In this study, we compared the effect of liver inflammation induced by the Toll-like receptor 4 ligand lipopolysaccharide (LPS) with that of a persistent virus, lymphocytic choriomeningitis virus (LCMV) clone 13, on early innate intrahepatic immune responses in mice. LCMV infection induces a remarkable influx of inflammatory monocytes in the liver within 24 h, accompanied by increased transcript levels of several proinflammatory cytokines and chemokines in whole liver. Importantly, while a single LPS injection results in similar recruitment of inflammatory monocytes to the liver, the functional properties of the infiltrating cells are dramatically different in response to LPS versus LCMV infection. In fact, intrahepatic inflammatory monocytes are skewed toward a secretory phenotype with impaired phagocytosis in LCMV-induced liver inflammation but exhibit increased endocytic capacity after LPS challenge. In contrast, F4/80high-Kupffer cells retain their steady-state endocytic functions upon LCMV infection. Strikingly, the gene expression levels of inflammatory monocytes dramatically change upon LCMV exposure and resemble those of Kupffer cells. Since inflammatory monocytes outnumber Kupffer cells 24 h after LCMV infection, it is highly likely that inflammatory monocytes contribute to the intrahepatic inflammatory response during the early phase of infection. Our findings are instrumental in understanding the early immunological events during virus-induced liver disease and point toward inflammatory monocytes as potential target cells for future treatment options in viral hepatitis.IMPORTANCEInsights into how the immune system deals with hepatitis B virus (HBV) and HCV are scarce due to the lack of adequate animal model systems. This knowledge is, however, crucial to developing new antiviral strategies aimed at eradicating these chronic infections. We model virus-host interactions during the initial phase of liver inflammation 24 h after inoculating mice with LCMV. We show that infected Kupffer cells are rapidly outnumbered by infiltrating inflammatory monocytes, which secrete proinflammatory cytokines but are less phagocytic. Nevertheless, these recruited inflammatory monocytes start to resemble Kupffer cells on a transcript level. The specificity of these cellular changes for virus-induced liver inflammation is corroborated by demonstrating opposite functions of monocytes after LPS challenge. Overall, this demonstrates the enormous functional and genetic plasticity of infiltrating monocytes and identifies them as an important target cell for future treatment regimens.

scholarly journals Systems biological assessment of human immunity to BNT162b2 mRNA vaccination

2021 ◽  
Author(s):  
Bali Pulendran ◽  
Prabhu S Arunachalam
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Booster Vaccination ◽  
Fold Increase ◽  
Biological Assessment ◽  
Interferon Response ◽  
Innate Response ◽  
Booster Immunization ◽  
Inflammatory Monocytes

Abstract The emergency use authorization of two COVID-19 mRNA vaccines in less than a year since the emergence of SARS-CoV-2, represents a landmark in vaccinology1,2. Yet, how mRNA vaccines stimulate the immune system to elicit protective immune responses is unknown. Here we used a systems biological approach to comprehensively profile the innate and adaptive immune responses in 56 healthy volunteers vaccinated with the Pfizer-BioNTech mRNA vaccine. Vaccination resulted in robust production of neutralizing antibodies (nAbs) against the parent strain and the variant of concern, B.1.351, but no induction of autoantibodies, and significant increases in antigen-specific polyfunctional CD4 and CD8 T cells after the second dose. The innate response induced within the first 2 days of booster vaccination was profoundly increased, relative to the response at corresponding times after priming. Thus, there was a striking increase in the: (i) frequency of CD14+CD16+ inflammatory monocytes; (ii) concentration of IFN-y in the plasma, which correlated with enhanced pSTAT3 and pSTAT1 levels in monocytes and T cells; and (iii) transcriptional signatures of innate responses characteristic of antiviral vaccine responses against pandemic influenza, HIV and Ebola, within 2 days following booster vaccination compared to primary vaccination. Consistent with these observations, single-cell transcriptomics analysis of 242,479 leukocytes demonstrated a ~100-fold increase in the frequency of a myeloid cluster, enriched in a signature of interferon-response transcription factors (TFs) and reduced in AP-1 TFs, one day after secondary immunization, at day 21. Finally, we delineated distinct molecular pathways of innate activation that correlate with CD8 T cell and nAb responses and identified an early monocyte-related signature that was associated with the breadth of the nAb response against the B1.351 variant strain. Collectively, these data provide insights into the immune responses induced by mRNA vaccines and demonstrate their capacity to stimulate an enhanced innate response following booster immunization.

scholarly journals Enhanced Virus Clearance by Early Inducible Lymphocytic Choriomeningitis Virus-Neutralizing Antibodies in Immunoglobulin-Transgenic Mice

1998 ◽  
Vol 72 (3) ◽  
pp. 2253-2258 ◽  
Author(s):  
Peter Seiler ◽  
Ulrich Kalinke ◽  
Thomas Rülicke ◽  
Etienne M. Bucher ◽  
Christian Böse ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Antibody Response ◽  
Acute Phase ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Lymphocytic Choriomeningitis ◽  
Lymphocytic Choriomeningitis Virus ◽  
Immunoglobulin M ◽  
Neutralizing Monoclonal Antibody ◽  
Lcmv Infection

ABSTRACT Following infection of mice with lymphocytic choriomeningitis virus (LCMV), virus-neutralizing antibodies appear late, after 30 to 60 days. Such neutralizing antibodies play an important role in protection against reinfection. To analyze whether a neutralizing antibody response which developed earlier could contribute to LCMV clearance during the acute phase of infection, we generated transgenic mice expressing LCMV-neutralizing antibodies. Transgenic mice expressing the immunoglobulin μ heavy chain of the LCMV-neutralizing monoclonal antibody KL25 (H25 transgenic mice) mounted LCMV-neutralizing immunoglobulin M (IgM) serum titers within 8 days after infection. This early inducible LCMV-neutralizing antibody response significantly improved the host’s capacity to clear the infection and did not cause an enhancement of disease after intracerebral (i.c.) LCMV infection. In contrast, mice which had been passively administered LCMV-neutralizing antibodies and transgenic mice exhibiting spontaneous LCMV-neutralizing IgM serum titers (HL25 transgenic mice expressing the immunoglobulin μ heavy and the κ light chain) showed an enhancement of disease after i.c. LCMV infection. Thus, early-inducible LCMV-neutralizing antibodies can contribute to viral clearance in the acute phase of the infection and do not cause antibody-dependent enhancement of disease.

Endothelial Cell Protein S Synthesis Is Upregulated by the Complex of IL-6 and Soluble IL-6 Receptor

1997 ◽  
Vol 77 (05) ◽  
pp. 1014-1019 ◽  
Author(s):  
W Craig Hooper ◽  
Donald J Phillips ◽  
Bruce L Evatt
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Line ◽  
Neutralizing Antibodies ◽  
Hepatoma Cell ◽  
Protein S ◽  
Oncostatin M ◽  
Cell Protein ◽  
Microvascular Endothelial Cell ◽  
Hepatoma Cell Line

SummaryWe have recently demonstrated that the proinflammatory cytokine, interleukin-6 (IL-6), could upregulate the production of protein S in the human hepatoma cell line, HepG-2, but not in endothelial cells. In this study, we have demonstrated that the combination of exogenous IL-6 and soluble IL-6 receptor (sIL-6R) could significantly upregulate protein S production in both primary human umbilical vein endothelial cells (HUVEC) and in the immortalized human microvascular endothelial cell line, HMEC-1. The IL-6/sIL-6R complex was also able to rapidly induce tyrosine phosphorylation of the IL-6 transducer, gpl30. Neutralizing antibodies directed against either IL-6 or gpl30 blocked protein S upregulation by the IL-6/sIL-6R complex. It was also observed that exogenous sIL-6R could also upregulate protein S by forming a complex with IL-6 constitutively produced by the endothelial cell. Two other cytokines which also utilize the gpl30 receptor, oncostatin M (OSM) and leukemia inhibitory factor (LIF), were also able to upregulate endothelial cell protein S. This study demonstrates a mechanism that allows endothelial cells to respond to IL-6 and also illustrates the potential importance of circulating soluble receptors in the regulation of the anticoagulation pathway.

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