scholarly journals Evolution during primary HIV infection does not require adaptive immune selection

2020 ◽  
Author(s):  
David A Swan ◽  
Morgane Rolland ◽  
Joshua Herbeck ◽  
Joshua T Schiffer ◽  
Daniel B Reeves
Keyword(s):  
Viral Load ◽  
Immune System ◽  
Hiv Infection ◽  
Evolutionary Dynamics ◽  
Immune Cell ◽  
Adaptive Immune System ◽  
Viral Fitness ◽  
Immune Cell Population ◽  
Adaptive Immune

AbstractModern HIV research depends crucially on both viral sequencing and population measurements. To directly link mechanistic biological processes and evolutionary dynamics during HIV infection, we developed multiple within-host phylodynamic (wi-phy) models of HIV primary infection for comparative validation against viral load and evolutionary dynamics data. The most parsimonious and accurate model required no positive selection, suggesting that the host adaptive immune system reduces viral load, but does not drive observed viral evolution. Rather, random genetic drift primarily dictates fitness changes. These results hold during early infection, and even during chronic infection when selection has been observed, viral fitness distributions are not largely different from in vitro distributions that emerge without adaptive immunity. These results highlight how phylogenetic inference must consider complex viral and immune-cell population dynamics to gain accurate mechanistic insights.One sentence summaryThrough the lens of a unified population and phylodynamic model, current data show the first wave of HIV mutations are not driven by selection by the adaptive immune system.

scholarly journals Bacterial toxins and the immune system

2005 ◽  
Vol 201 (3) ◽  
pp. 321-323 ◽  
Author(s):  
Jorge E. Galán
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Persistent Infection ◽  
Immune Cell ◽  
Adaptive Immune Response ◽  
Adaptive Immune System ◽  
Bacterial Toxins ◽  
Cell Functions ◽  
Adaptive Immune

Microorganisms that cause persistent infection often exhibit specific adaptations that allow them to avoid the adaptive immune response. Recently, several bacterial toxins have been shown in vitro to disrupt immune cell functions. However, it remains to be established whether these activities are relevant during infection and whether these toxins have specifically evolved to disrupt the adaptive immune system.

scholarly journals Optimizing Dendritic Cell-Based Immunotherapy: Tackling the Complexity of Different Arms of the Immune System

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Ilse Van Brussel ◽  
Zwi N. Berneman ◽  
Nathalie Cools
Keyword(s):  
Immune System ◽  
Dendritic Cell ◽  
Immune Responses ◽  
Adaptive Immune System ◽  
Cellular Mechanisms ◽  
Adaptive Immune Responses ◽  
Adaptive Immune ◽  
New Ideas ◽  
And Function

Earlier investigations have revealed a surprising complexity and variety in the range of interaction between cells of the innate and adaptive immune system. Our understanding of the specialized roles of dendritic cell (DC) subsets in innate and adaptive immune responses has been significantly advanced over the years. Because of their immunoregulatory capacities and because very small numbers of activated DC are highly efficient at generating immune responses against antigens, DCs have been vigorously used in clinical trials in order to elicit or amplify immune responses against cancer and chronic infectious diseases. A better insight in DC immunobiology and function has stimulated many new ideas regarding the potential ways forward to improve DC therapy in a more fundamental way. Here, we discuss the continuous search for optimal in vitro conditions in order to generate clinical-grade DC with a potent immunogenic potential. For this, we explore the molecular and cellular mechanisms underlying adequate immune responses and focus on most favourable DC culture regimens and activation stimuli in humans. We envisage that by combining each of the features outlined in the current paper into a unified strategy, DC-based vaccines may advance to a higher level of effectiveness.

scholarly journals How important is CRISPR-Cas for protecting natural populations of bacteria against infections by mobile genetic elements?

2020 ◽  
Author(s):  
Edze Westra ◽  
Bruce Levin
Keyword(s):  
Computer Simulation ◽  
Immune System ◽  
Natural Populations ◽  
Adaptive Immune System ◽  
Simulation Models ◽  
Mobile Genetic Elements ◽  
Genetic Elements ◽  
Adaptive Immune ◽  
Computer Simulation Models

AbstractArticles on CRISPR commonly open with some variant of the phrase ‘these short-palindromic repeats and their associated endonucleases (Cas) are an adaptive immune system that exists to protect bacteria and archaea from viruses and infections with other mobile genetic elements’. There is an abundance of genomic data consistent with the hypothesis that CRISPR plays this role in natural populations of bacteria and archaea, and experimental demonstrations with a few species of bacteria and their phage and plasmids show that CRISPR-Cas systems can play this role in vitro. Not at all clear are the ubiquity, magnitude and nature of the contribution of CRISPR-Cas systems to the ecology and evolution of natural populations of microbes, and the strength of selection mediated by different types of phage and plasmids to the evolution and maintenance of CRISPR-Cas systems. In this perspective, with the aid of heuristic mathematical-computer simulation models, we explore the a priori conditions under which exposure to lytic and temperate phage and conjugative plasmids will select for and maintain CRISPR-Cas systems in populations of bacteria and archaea. We review the existing literature addressing these ecological and evolutionary questions and highlight the experimental and other evidence needed to fully understand the conditions responsible for the evolution and maintenance of CRISPR-Cas systems and the contribution of these systems to the ecology and evolution of bacteria, archaea and the mobile genetic elements that infect them.SignificanceThere is no question about the importance and utility of CRISPR-Cas for editing and modifying genomes. On the other hand, the mechanisms responsible for the evolution and maintenance of these systems and the magnitude of their importance to the ecology and evolution of bacteria, archaea and their infectious DNAs, are not at all clear. With the aid of heuristic mathematical – computer simulation models and reviews of the existing literature, we raise questions that have to be answered to elucidate the contribution of selection – mediated by phage and plasmids – to the evolution and maintenance of this adaptive immune system and its consequences for the ecology and evolution of prokaryotes and their viruses and plasmids.

scholarly journals Persistent anti-heart autoimmunity causes cardiomyocyte damage in chronic heart failure

2019 ◽  
Author(s):  
Amalia Sintou ◽  
Sarah el Rifai ◽  
Catherine Mansfield ◽  
Jose L. Sanchez Alonso ◽  
Stephen M. Rothery ◽  
...  
Keyword(s):  
Heart Failure ◽  
Immune System ◽  
Chronic Heart Failure ◽  
Adaptive Immune System ◽  
Tissue Destruction ◽  
Humoral Factors ◽  
Adaptive Immune ◽  
Promising Target ◽  
Self Tolerance

AbstractAlthough clinicians and researchers have long appreciated the detrimental effects of excessive acute inflammation after myocardial infarction (MI), less is known about the role of the adaptive immune system in MI complications including heart failure. Yet, abundant cardiac self-antigens released from necrotic cardiomyocytes in a highly inflammatory environment are likely to overwhelm peripheral mechanisms of immunological self-tolerance and adaptive auto-reactivity against the heart may cause ongoing tissue destruction and exacerbate progression to chronic heart failure (CHF).Here, we confirm that the adaptive immune system is indeed persistently active in CHF due to ischemic heart disease triggered by MI in rats. Heart draining mediastinal lymph nodes contain active secondary follicles with mature class-switched IgG2a positive cells, and mature anti-heart auto-antibodies binding to cardiac epitopes are still present in serum as late as 16 weeks after MI. When applied to healthy cardiomyocytes in vitro, humoral factors present in CHF serum promoted apoptosis, cytotoxicity and signs of hypertrophy.These findings directly implicate post-MI autoimmunity as an integral feature of CHF progression, constituting a roadblock to effective regeneration and a promising target for therapeutic intervention.

scholarly journals Monocyte-lymphocyte cross-communication via soluble CD163 directly links innate immune system activation and adaptive immune system suppression following ischemic stroke

2017 ◽  
Author(s):  
Grant C. O’Connell ◽  
Connie S. Tennant ◽  
Noelle Lucke-Wold ◽  
Yasser Kabbani ◽  
Abdul R. Tarabishy ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Immune System ◽  
Innate Immune System ◽  
Healthy Donor ◽  
Adaptive Immune System ◽  
Innate Immune ◽  
Stroke Patients ◽  
Adaptive Immune ◽  
Soluble Cd163

AbstractCD163 is a scavenger receptor expressed on innate immune cell populations which can be shed from the plasma membrane via the metalloprotease ADAM17 to generate a soluble peptide with lympho-inhibitory properties. The purpose of this study was to investigate CD163 as a possible effector of stroke-induced adaptive immune system suppression. Liquid biopsies were collected from ischemic stroke patients (n=39), neurologically asymptomatic controls (n=20), and stroke mimics (n=20) within 24 hours of symptom onset. Peripheral blood ADAM17 activity and soluble CD163 levels were elevated in stroke patients relative to non-stroke control groups, and negatively associated with post-stroke lymphocyte counts. Subsequent in vitro experiments suggested that this stroke-induced elevation in circulating soluble CD163 likely originates from activated monocytic cells, as serum from stroke patients stimulated ADAM17-dependant CD163 shedding from healthy donor-derived monocytes. Additional in vitro experiments demonstrated that stroke-induced elevations in circulating soluble CD163 can elicit direct suppressive effects on the adaptive immune system, as serum from stroke patients inhibited the proliferation of healthy donor-derived lymphocytes, an effect which was attenuated following serum CD163 depletion. Collectively, these observations provide novel evidence that the innate immune system employs protective mechanisms aimed at mitigating the risk of post-stroke autoimmune complications driven by adaptive immune system overactivation, and that CD163 is key mediator of this phenomenon.

scholarly journals Inflammation and Cell Death of the Innate and Adaptive Immune System during Sepsis

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1011
Author(s):  
Christina Nedeva
Keyword(s):  
Cell Death ◽  
Immune System ◽  
Immune Activation ◽  
Immune Cell ◽  
Medical Condition ◽  
Treatment Options ◽  
Disease Onset ◽  
Adaptive Immune System ◽  
Comprehensive Overview ◽  
Adaptive Immune

Sepsis is a life-threatening medical condition that occurs when the host has an uncontrolled or abnormal immune response to overwhelming infection. It is now widely accepted that sepsis occurs in two concurrent phases, which consist of an initial immune activation phase followed by a chronic immunosuppressive phase, leading to immune cell death. Depending on the severity of the disease and the pathogen involved, the hosts immune system may not fully recover, leading to ongoing complications proceeding the initial infection. As such, sepsis remains one of the leading causes of morbidity and mortality world-wide, with treatment options limited to general treatment in intensive care units (ICU). Lack of specific treatments available for sepsis is mostly due to our limited knowledge of the immuno-physiology associated with the disease. This review will provide a comprehensive overview of the mechanisms and cell types involved in eliciting infection-induced immune activation from both the innate and adaptive immune system during sepsis. In addition, the mechanisms leading to immune cell death following hyperactivation of immune cells will be explored. The evaluation and better understanding of the cellular and systemic responses leading to disease onset could eventuate into the development of much needed therapies to combat this unrelenting disease.

scholarly journals Hippo Pathway in Mammalian Adaptive Immune System

Cells ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 398 ◽  
Author(s):  
Takayoshi Yamauchi ◽  
Toshiro Moroishi
Keyword(s):  
Immune System ◽  
Immune Responses ◽  
Immune Cell ◽  
Hippo Pathway ◽  
Adaptive Immune System ◽  
Signaling Mechanism ◽  
Adaptive Immune ◽  
Adaptive Immune Cell ◽  
Cancer Pathogenesis ◽  
The Hippo Pathway

The Hippo pathway was originally identified as an evolutionarily-conserved signaling mechanism that contributes to the control of organ size. It was then rapidly expanded as a key pathway in the regulation of tissue development, regeneration, and cancer pathogenesis. The increasing amount of evidence in recent years has also connected this pathway to the regulation of innate and adaptive immune responses. Notably, the Hippo pathway has been revealed to play a pivotal role in adaptive immune cell lineages, as represented by the patients with T- and B-cell lymphopenia exhibiting defective expressions of the pathway component. The complex regulatory mechanisms of and by the Hippo pathway have also been evident as alternative signal transductions are employed in some immune cell types. In this review article, we summarize the current understanding of the emerging roles of the Hippo pathway in adaptive immune cell development and differentiation. We also highlight the recent findings concerning the dual functions of the Hippo pathway in autoimmunity and anti-cancer immune responses and discuss the key open questions in the interplay between the Hippo pathway and the mammalian immune system.

scholarly journals NBAS Variants Are Associated with Quantitative and Qualitative NK and B Cell Deficiency

2021 ◽  
Author(s):  
Dominic Lenz ◽  
Jens Pahl ◽  
Fabian Hauck ◽  
Seham Alameer ◽  
Meena Balasubramanian ◽  
...  
Keyword(s):  
Immune System ◽  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Adaptive Immune System ◽  
Target Cells ◽  
Multisystem Disorder ◽  
Adaptive Immune ◽  
B Cell Deficiency

Abstract Purpose Biallelic pathogenic NBAS variants manifest as a multisystem disorder with heterogeneous clinical phenotypes such as recurrent acute liver failure, growth retardation, and susceptibility to infections. This study explores how NBAS-associated disease affects cells of the innate and adaptive immune system. Methods Clinical and laboratory parameters were combined with functional multi-parametric immunophenotyping methods in fifteen NBAS-deficient patients to discover possible alterations in their immune system. Results Our study revealed reduced absolute numbers of mature CD56dim natural killer (NK) cells. Notably, the residual NK cell population in NBAS-deficient patients exerted a lower potential for activation and degranulation in response to K562 target cells, suggesting an NK cell–intrinsic role for NBAS in the release of cytotoxic granules. NBAS-deficient NK cell activation and degranulation was normalized upon pre-activation by IL-2 in vitro, suggesting that functional impairment was reversible. In addition, we observed a reduced number of naïve B cells in the peripheral blood associated with hypogammaglobulinemia. Conclusion In summary, we demonstrate that pathogenic biallelic variants in NBAS are associated with dysfunctional NK cells as well as impaired adaptive humoral immunity.

scholarly journals Tipping the Scales With Zebrafish to Understand Adaptive Tumor Immunity

2021 ◽  
Vol 9 ◽  
Author(s):  
Kelly Z. Miao ◽  
Grace Y. Kim ◽  
Grace K. Meara ◽  
Xiaodan Qin ◽  
Hui Feng
Keyword(s):  
Immune System ◽  
Tumor Immunity ◽  
Immune Cell ◽  
Driving Forces ◽  
Adaptive Immune System ◽  
Experimental System ◽  
Dynamic Interactions ◽  
Adaptive Immune ◽  
Anti Cancer ◽  
New Frontier

The future of improved immunotherapy against cancer depends on an in-depth understanding of the dynamic interactions between the immune system and tumors. Over the past two decades, the zebrafish has served as a valuable model system to provide fresh insights into both the development of the immune system and the etiologies of many different cancers. This well-established foundation of knowledge combined with the imaging and genetic capacities of the zebrafish provides a new frontier in cancer immunology research. In this review, we provide an overview of the development of the zebrafish immune system along with a side-by-side comparison of its human counterpart. We then introduce components of the adaptive immune system with a focus on their roles in the tumor microenvironment (TME) of teleosts. In addition, we summarize zebrafish models developed for the study of cancer and adaptive immunity along with other available tools and technology afforded by this experimental system. Finally, we discuss some recent research conducted using the zebrafish to investigate adaptive immune cell-tumor interactions. Without a doubt, the zebrafish will arise as one of the driving forces to help expand the knowledge of tumor immunity and facilitate the development of improved anti-cancer immunotherapy in the foreseeable future.

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