scholarly journals Decay of Fc-dependent antibody functions after mild to moderate COVID-19

2020 ◽  
Author(s):  
Wen Shi Lee ◽  
Kevin John Selva ◽  
Samantha K. Davis ◽  
Bruce D. Wines ◽  
Arnold Reynaldi ◽  
...  
Keyword(s):  
Immune Cells ◽  
Antibody Dependent Cellular Cytotoxicity ◽  
Neutralising Antibodies ◽  
Specific Antibodies ◽  
Effector Functions ◽  
Adaptive Immune ◽  
Adaptive Immune Cells ◽  
Specific Igg ◽  
Serial Samples ◽  
Over Time

AbstractThe capacity of antibodies to engage with innate and adaptive immune cells via the Fc region is important in preventing and controlling many infectious diseases, and is likely critical in SARS-CoV-2 infection. The evolution of such antibodies during convalescence from COVID-19 is largely unknown. We developed novel assays to measure Fc-dependent antibody functions against SARS-CoV-2 spike (S)-expressing cells in serial samples from a cohort of 53 subjects primarily with mild-moderate COVID-19, out to a maximum of 149 days post-infection. We found that S-specific antibodies capable of engaging dimeric FcγRIIa and FcγRIIIa decayed linearly over time. S-specific antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent phagocytosis (ADP) activity within plasma declined linearly as well, in line with the decay of S-specific IgG. Although there was significant decay in S-specific plasma ADCC and ADP activity, they remained readily detectable by all assays in 94% of our cohort at the last timepoint studied, in contrast with neutralisation activity which was only detectable in 70% of our cohort by the last timepoint. Our results suggest that Fc effector functions such as ADCC and ADP could contribute to the durability of SARS-CoV-2 immunity, particularly late in convalescence when neutralising antibodies have waned. Understanding the protective potential of antibody Fc effector functions is critical for defining the durability of immunity generated by infection or vaccination.

scholarly journals Lactate-Dependent Regulation of Immune Responses by Dendritic Cells and Macrophages

2021 ◽  
Vol 12 ◽  
Author(s):  
Indumathi Manoharan ◽  
Puttur D. Prasad ◽  
Muthusamy Thangaraju ◽  
Santhakumar Manicassamy
Keyword(s):  
Dendritic Cells ◽  
Immune Responses ◽  
Immune Cells ◽  
Adaptive Immune Responses ◽  
Effector Functions ◽  
Tissue Microenvironment ◽  
Adaptive Immune ◽  
Pathological Conditions ◽  
Recent Advances ◽  
Adaptive Immune Cells

For decades, lactate has been considered an innocuous bystander metabolite of cellular metabolism. However, emerging studies show that lactate acts as a complex immunomodulatory molecule that controls innate and adaptive immune cells’ effector functions. Thus, recent advances point to lactate as an essential and novel signaling molecule that shapes innate and adaptive immune responses in the intestine and systemic sites. Here, we review these recent advances in the context of the pleiotropic effects of lactate in regulating diverse functions of immune cells in the tissue microenvironment and under pathological conditions.

Platelets: Angels and demons dancing on the immune stage. Nutrition conducts the orchestra

2020 ◽  
Vol 20 ◽  
Author(s):  
Thea Magrone ◽  
Manrico Magrone ◽  
Matteo Antonio Russo ◽  
Emilio Jirillo
Keyword(s):  
Platelet Function ◽  
Immune Cells ◽  
Dual Role ◽  
Immune Functions ◽  
Omega 3 ◽  
Adaptive Immune ◽  
Cytokines And Chemokines ◽  
Adaptive Immune Cells ◽  
Immune Mediated ◽  
Inflammatory Processes

Background: Platelets are cellular fragments derived from bone-marrow megacaryocytes and they are mostly involved in haemostasis and coagulation. However, according to recent data, platelets are able to perform novel immune functions. In fact, they possess a receptorial armamentarium on their membrane for interacting with innate and adaptive immune cells. In addition, platelets also secrete granules which contain cytokines and chemokines for activating and recruiting even distant immune cells. Objectives: The participation of platelets in inflammatory processes will be discussed also in view of their dual role in terms of triggering or resolving inflammation. Involvement of platelets in disease will be illustrated, pointing to their versatile function to either up- or down-regulate pathological mechanisms. Finally, despite the availability of some anti-platelet agents, such as aspirin, dietary manipulation of platelet function is currently investigated. In this regard, special emphasis will be placed on dietary omega-3 polyunsaturated fatty acids (PUFAs) and polyphenol effects on platelets. Conclusion: Platelets play a dual role in inflammatory-immune-mediated diseases either activating or deactivating immune cells. Diet based on substances, such as omega-3 PUFAs and polyphenols, may act as a modulator of platelet function, even if more clinical trials are needed to corroborate such a contention.

scholarly journals Tuning cancer fate: the unremitting role of host immunity

Open Biology ◽  
2017 ◽  
Vol 7 (4) ◽  
pp. 170006 ◽  
Author(s):  
B. Calì ◽  
B. Molon ◽  
A. Viola
Keyword(s):  
Immune Cells ◽  
Immune Cell ◽  
Tumour Progression ◽  
Host Immunity ◽  
Adaptive Immune ◽  
Adaptive Immune Cells ◽  
Immune Mediated ◽  
Immune Cell Subsets ◽  
Therapeutic Protocols

Host immunity plays a central and complex role in dictating tumour progression. Solid tumours are commonly infiltrated by a large number of immune cells that dynamically interact with the surrounding microenvironment. At first, innate and adaptive immune cells successfully cooperate to eradicate microcolonies of transformed cells. Concomitantly, surviving tumour clones start to proliferate and harness immune responses by specifically hijacking anti-tumour effector mechanisms and fostering the accumulation of immunosuppressive immune cell subsets at the tumour site. This pliable interplay between immune and malignant cells is a relentless process that has been concisely organized in three different phases: elimination, equilibrium and escape. In this review, we aim to depict the distinct immune cell subsets and immune-mediated responses characterizing the tumour landscape throughout the three interconnected phases. Importantly, the identification of key immune players and molecules involved in the dynamic crosstalk between tumour and immune system has been crucial for the introduction of reliable prognostic factors and effective therapeutic protocols against cancers.

IN VIVO IMMUNOSUPPRESSIVE EFFECTS OF INTRAVENOUS IMMUNOGLOBULIN ON INNATE AND ADAPTIVE IMMUNE CELLS INVOLVED IN ALLOGRAFT REJECTION

2010 ◽  
Vol 90 ◽  
pp. 395
Author(s):  
A. S. Tjon ◽  
T. Tha-In ◽  
H. J. Metselaar ◽  
L. V.D. Laan ◽  
Z. M. Groothuismink ◽  
...  
Keyword(s):  
Intravenous Immunoglobulin ◽  
Immune Cells ◽  
Allograft Rejection ◽  
Adaptive Immune ◽  
Adaptive Immune Cells

scholarly journals Broadly Neutralizing Hemagglutinin Stalk-Specific Antibodies Induce Potent Phagocytosis of Immune Complexes by Neutrophils in an Fc-Dependent Manner

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Caitlin E. Mullarkey ◽  
Mark J. Bailey ◽  
Diana A. Golubeva ◽  
Gene S. Tan ◽  
Raffael Nachbagauer ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Fc Receptor ◽  
Igg Antibodies ◽  
Specific Antibodies ◽  
Effector Functions ◽  
Iga Antibodies ◽  
Specific Igg ◽  
Optimal Protection ◽  
Specific Igg Antibodies

ABSTRACTBroadly neutralizing antibodies that recognize the conserved hemagglutinin (HA) stalk have emerged as exciting new biotherapeutic tools to combat seasonal and pandemic influenza viruses. Our general understanding of the mechanisms by which stalk-specific antibodies achieve protection is rapidly evolving. It has recently been demonstrated that broadly neutralizing HA stalk-specific IgG antibodies require Fc-Fcγ receptor (FcγR) interactions for optimal protectionin vivo. Here we examine the neutrophil effector functions induced by stalk-specific antibodies. As the most abundant subset of blood leukocytes, neutrophils represent a critical innate effector cell population and serve an instrumental role in orchestrating downstream adaptive responses to influenza virus infection. Yet, the interplay of HA stalk-specific IgG, Fc-FcγR engagement, and neutrophils has remained largely uncharacterized. Using anin vitroassay to detect the production of reactive oxygen species (ROS), we show that human and mouse monoclonal HA stalk-specific IgG antibodies are able to induce the production of ROS by neutrophils, while HA head-specific antibodies do not. Furthermore, our results indicate that the production of ROS is dependent on Fc receptor (FcR) engagement and phagocytosis. We went on to assess the ability of monoclonal HA stalk-specific IgA antibodies to induce ROS. Consistent with our findings for monoclonal IgGs, only HA stalk-specific IgA antibodies elicited ROS production by neutrophils. This induction is dependent on the engagement of FcαR1. Taken together, our findings describe a novel FcR-dependent effector function induced by HA stalk-specific IgG and IgA antibodies, and importantly, our studies shed light on the mechanisms by which HA stalk-specific antibodies achieve protection.IMPORTANCEThe present study provides evidence that broadly neutralizing HA stalk-specific antibodies induce downstream Fc-mediated neutrophil effector functions. In addition to their ability to neutralize, this class of antibodies has been shown to rely on Fc-Fc receptor interactions for optimal protectionin vivo. Curiously, neutralizing antibodies that bind the HA head domain do not require such interactions. Our findings build on these previous observations and provide a more complete picture of the relationship between stalk-specific antibodies and cells of the innate immune compartment. Furthermore, our data suggest that the ability of HA stalk-specific antibodies to mediate Fc-Fc receptor engagement is epitope dependent. Overall, this work will inform the rational design of improved influenza virus vaccines and therapeutics.

scholarly journals The Hygiene Hypothesis and New Perspectives—Current Challenges Meeting an Old Postulate

2021 ◽  
Vol 12 ◽  
Author(s):  
Holger Garn ◽  
Daniel Piotr Potaczek ◽  
Petra Ina Pfefferle
Keyword(s):  
Immune Cells ◽  
Hygiene Hypothesis ◽  
Fine Tuning ◽  
Global Changes ◽  
Industrialized Countries ◽  
New Developments ◽  
Asthma Phenotypes ◽  
Adaptive Immune ◽  
Adaptive Immune Cells

During its 30 years history, the Hygiene Hypothesis has shown itself to be adaptable whenever it has been challenged by new scientific developments and this is a still a continuously ongoing process. In this regard, the mini review aims to discuss some selected new developments in relation to their impact on further fine-tuning and expansion of the Hygiene Hypothesis. This will include the role of recently discovered classes of innate and adaptive immune cells that challenges the old Th1/Th2 paradigm, the applicability of the Hygiene Hypothesis to newly identified allergy/asthma phenotypes with diverse underlying pathomechanistic endotypes, and the increasing knowledge derived from epigenetic studies that leads to better understanding of mechanisms involved in the translation of environmental impacts on biological systems. Further, we discuss in brief the expansion of the Hygiene Hypothesis to other disease areas like psychiatric disorders and cancer and conclude that the continuously developing Hygiene Hypothesis may provide a more generalized explanation for health burden in highly industrialized countries also relation to global changes.

scholarly journals The impact of body mass index on adaptive immune cells in the human bone marrow

2020 ◽  
Author(s):  
Luca Pangrazzi ◽  
Erin Naismith ◽  
Carina Miggitsch ◽  
Jose’ Antonio Carmona Arana ◽  
Michael Keller ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Bone Marrow ◽  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Immune Cells ◽  
Memory T Cells ◽  
T Cell Subsets ◽  
Adaptive Immune ◽  
Adaptive Immune Cells

Abstract Background. Obesity has been associated with chronic inflammation and oxidative stress. Both conditions play a determinant role in the pathogenesis of age-related diseases, such as immunosenescence. Adipose tissue can modulate the function of the immune system with the secretion of molecules influencing the phenotype of immune cells. The importance of the bone marrow (BM) in the maintenance of antigen-experienced adaptive immune cells has been documented in mice. Recently, some groups have investigated the survival of effector/memory T cells in the human BM. Despite this, whether high body mass index (BMI) may affect immune cells in the BM and the production of molecules supporting the maintenance of these cells it is unknown.Methods. Using flow cytometry, the frequency and the phenotype of immune cell populations were measured in paired BM and PB samples obtained from persons with different BMI. Furthermore, the expression of BM cytokines was assessed. The influence of cytomegalovirus (CMV) on T cell subsets was additionally considered, dividing the donors into the CMV- and CMV+ groups.Results. Our study suggests that increased BMI may affect both the maintenance and the phenotype of adaptive immune cells in the BM. While the BM levels of IL-15 and IL-6, supporting the survival of highly differentiated T cells, and oxygen radicals increased in overweight persons, the production of IFNγ and TNF by CD8+ T cells was reduced. In addition, the frequency of B cells and CD4+ T cells positively correlated with BMI in the BM of CMV- persons. Finally, the frequency of several T cell subsets, and the expression of senescence/exhaustion markers within these subpopulations, were affected by BMI. In particular, the levels of bona fide memory T cells may be reduced in overweight persons.Conclusion. Our work suggests that, in addition to aging and CMV, obesity may represent an additional risk factor for immunosenescence in adaptive immune cells. Metabolic interventions may help in improving the fitness of the immune system in the elderly.

scholarly journals Type III Interferons: Emerging Roles in Autoimmunity

2021 ◽  
Vol 12 ◽  
Author(s):  
Sindhu Manivasagam ◽  
Robyn S. Klein
Keyword(s):  
Immune Cells ◽  
T Cell Differentiation ◽  
Cd4 T Cell ◽  
Th1 Cells ◽  
Type Iii ◽  
Adaptive Immune ◽  
Adaptive Immune Cells ◽  
Cellular Specificity ◽  
Epithelial Barriers ◽  
Antimicrobial Immunity

Type III interferons (IFNs) or the lambda IFNs (IFNLs or IFN-λs) are antimicrobial cytokines that play key roles in immune host defense at endothelial and epithelial barriers. IFNLs signal via their heterodimeric receptor, comprised of two subunits, IFNLR1 and interleukin (IL)10Rβ, which defines the cellular specificity of the responses to the cytokines. Recent studies show that IFNL signaling regulates CD4+ T cell differentiation, favoring Th1 cells, which has led to the identification of IFNL as a putative therapeutic target for autoimmune diseases. Here, we summarize the IFNL signaling pathways during antimicrobial immunity, IFNL-mediated immunomodulation of both innate and adaptive immune cells, and induction of autoimmunity.

Sign in / Sign up

Export Citation Format

Share Document