scholarly journals Perspective of HLA-G Induced Immunosuppression in SARS-CoV-2 Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Aifen Lin ◽  
Wei-Hua Yan
Keyword(s):  
Immune Responses ◽  
Viral Infections ◽  
Immune Cell ◽  
Nk Cell ◽  
Human Leukocyte ◽  
Detailed Knowledge ◽  
T Cell Apoptosis ◽  
Receptor Signalling ◽  
Poor Outcomes ◽  
Cellular Immune

COVID-19, the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has threatened public health worldwide. Host antiviral immune responses are essential for viral clearance and disease control, however, remarkably decreased immune cell numbers and exhaustion of host cellular immune responses are commonly observed in patients with COVID-19. This is of concern as it is closely associated with disease severity and poor outcomes. Human leukocyte antigen-G (HLA-G) is a ligand for multiple immune inhibitory receptors, whose expression can be upregulated by viral infections. HLA-G/receptor signalling, such as engagement with immunoglobulin-like transcript 2 (ILT-2) or ILT-4, not only inhibit T and natural killer (NK) cell immune responses, dendritic cell (DC) maturation, and B cell antibody production. It also induces regulatory cells such as myeloid-derived suppressive cells (MDSCs), or M2 type macrophages. Moreover, HLA-G interaction with CD8 and killer inhibitory receptor (KIR) 2DL4 can provoke T cell apoptosis and NK cell senescence. In this context, HLA-G can induce profound immune suppression, which favours the escape of SARS-CoV-2 from immune attack. Although detailed knowledge on the clinical relevance of HLA-G in SARS-CoV-2 infection is limited, we herein review the immunopathological aspects of HLA-G/receptor signalling in SARS-CoV-2 infection, which could provide a better understanding of COVID-19 disease progression and identify potential immunointerventions to counteract SARS-CoV-2 infection.

scholarly journals Towards Improved Use of Vaccination in the Control of Infectious Bronchitis and Newcastle Disease in Poultry: Understanding the Immunological Mechanisms

Vaccines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 20
Author(s):  
Anthony C. Ike ◽  
Chukwuebuka M. Ononugbo ◽  
Okechukwu J. Obi ◽  
Chisom J. Onu ◽  
Chinasa V. Olovo ◽  
...  
Keyword(s):  
Immune Responses ◽  
Newcastle Disease ◽  
Viral Infections ◽  
Advanced Technology ◽  
Global Food Security ◽  
Infectious Bronchitis ◽  
Immunological Mechanisms ◽  
Inactivated Vaccines ◽  
Successful Control ◽  
Cellular Immune

Infectious bronchitis (IB) and Newcastle disease (ND) are two important diseases of poultry and have remained a threat to the development of the poultry industry in many parts of the world. The immunology of avian has been well studied and numerous vaccines have been developed against the two viruses. Most of these vaccines are either inactivated vaccines or live attenuated vaccines. Inactivated vaccines induce weak cellular immune responses and require priming with live or other types of vaccines. Advanced technology has been used to produce several types of vaccines that can initiate prime immune responses. However, as a result of rapid genetic variations, the control of these two viral infections through vaccination has remained a challenge. Using various strategies such as combination of live attenuated and inactivated vaccines, development of IB/ND vaccines, use of DNA vaccines and transgenic plant vaccines, the problem is being surmounted. It is hoped that with increasing understanding of the immunological mechanisms in birds that are used in fighting these viruses, a more successful control of the diseases will be achieved. This will go a long way in contributing to global food security and the economic development of many developing countries, given the role of poultry in the attainment of these goals.

scholarly journals Distinct cellular immune signatures in acute Zika virus infection are associated with high or low persisting neutralizing antibody titers

2021 ◽  
Author(s):  
Elizabeth E. McCarthy ◽  
Pamela M. Odorizzi ◽  
Emma Lutz ◽  
Carolyn P. Smullin ◽  
Iliana Tenvooren ◽  
...  
Keyword(s):  
Zika Virus ◽  
Neutralizing Antibodies ◽  
Viral Infections ◽  
Immune Cell ◽  
Acute Infection ◽  
Neutralizing Antibody ◽  
Natural Immunity ◽  
Zikv Infection ◽  
Antibody Titers ◽  
Cellular Immune

Although the formation of a durable neutralizing antibody response after an acute viral infection is a key component of protective immunity, little is known about why some individuals generate high versus low neutralizing antibody titers to infection or vaccination. Infection with Zika virus (ZIKV) during pregnancy can cause devastating fetal outcomes, and efforts to understand natural immunity to this infection are essential for optimizing vaccine design. In this study, we leveraged the high-dimensional single-cell profiling capacity of mass cytometry (CyTOF) to deeply characterize the cellular immune response to acute and convalescent ZIKV infection in a cohort of blood donors in Puerto Rico incidentally found to be viremic during the 2015-2016 epidemic in the Americas. During acute ZIKV infection, we identified widely coordinated responses across innate and adaptive immune cell lineages. High frequencies of multiple activated innate immune subsets, as well as activated follicular helper CD4+ T cells and proliferating CD27-IgD- B cells, during acute infection were associated with high titers of ZIKV neutralizing antibodies at 6 months post-infection. On the other hand, low titers of ZIKV neutralizing antibodies were associated with immune features that suggested a cytotoxic-skewed immune "set-point." Our study offers insight into the cellular coordination of immune responses and identifies candidate cellular biomarkers that may offer predictive value in vaccine efficacy trials for ZIKV and other acute viral infections aimed at inducing high titers of neutralizing antibodies.

scholarly journals A functional spleen contributes to afucosylated IgG in humans

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Iwona Wojcik ◽  
David E. Schmidt ◽  
Lisa A. de Neef ◽  
Minke A. E. Rab ◽  
Bob Meek ◽  
...  
Keyword(s):  
Immune Responses ◽  
Viral Infections ◽  
Immune Cell ◽  
Lymphoid Organ ◽  
Immune Effector ◽  
Adaptive Immune ◽  
Wide Range ◽  
Humoral Responses ◽  
First Time

AbstractAs a lymphoid organ, the spleen hosts a wide range of immune cell populations, which not only remove blood-borne antigens, but also generate and regulate antigen-specific immune responses. In particular, the splenic microenvironment has been demonstrated to play a prominent role in adaptive immune responses to enveloped viral infections and alloantigens. During both types of immunizations, antigen-specific immunoglobulins G (IgGs) have been characterized by the reduced amount of fucose present on N-linked glycans of the fragment crystallizable (Fc) region. These glycans are essential for mediating the induction of immune effector functions. Therefore, we hypothesized that a spleen may modulate humoral responses and serve as a preferential site for afucosylated IgG responses, which potentially play a role in immune thrombocytopenia (ITP) pathogenesis. To determine the role of the spleen in IgG-Fc glycosylation, we performed IgG subclass-specific liquid chromatography–mass spectrometry (LC–MS) analysis of Fc glycosylation in a large cohort of individuals splenectomized due to trauma, due to ITP, or spherocytosis. IgG-Fc fucosylation was consistently increased after splenectomy, while no effects for IgG-Fc galactosylation and sialylation were observed. An increase in IgG1- and IgG2/3-Fc fucosylation level upon splenectomy has been reported here for the first time, suggesting that immune responses occurring in the spleen may be particularly prone to generate afucosylated IgG responses. Surprisingly, the level of total IgG-Fc fucosylation was decreased in ITP patients compared to healthy controls. Overall, our results suggest a yet unrecognized role of the spleen in either the induction or maintenance of afucosylated IgG responses by B cells.

scholarly journals Lymphopenia Caused by Virus Infections and the Mechanisms Beyond

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1876
Author(s):  
Zijing Guo ◽  
Zhidong Zhang ◽  
Meera Prajapati ◽  
Yanmin Li
Keyword(s):  
Immune Responses ◽  
Viral Infections ◽  
Clinical Course ◽  
Detailed Knowledge ◽  
Virus Infections ◽  
Adaptive Immune Responses ◽  
Therapeutic Targeting ◽  
Adaptive Immune

Viral infections can give rise to a systemic decrease in the total number of lymphocytes in the blood, referred to as lymphopenia. Lymphopenia may affect the host adaptive immune responses and impact the clinical course of acute viral infections. Detailed knowledge on how viruses induce lymphopenia would provide valuable information into the pathogenesis of viral infections and potential therapeutic targeting. In this review, the current progress of viruses-induced lymphopenia is summarized and the potential mechanisms and factors involved are discussed.

scholarly journals Immune Evasion Mechanism and AXL

2021 ◽  
Vol 11 ◽  
Author(s):  
Hye-Youn Son ◽  
Hwan-Kyu Jeong
Keyword(s):  
Tumor Microenvironment ◽  
Immune Responses ◽  
Signaling Pathway ◽  
Immune Evasion ◽  
Cell Activation ◽  
Immune Cell ◽  
Nk Cell ◽  
Multiple Cancer ◽  
Clinical Prognosis ◽  
Programmed Death

Extensive interest in cancer immunotherapy is reported according to the clinical importance of CTLA-4 and (PD-1/PD-L1) [programmed death (PD) and programmed death-ligand (PD-L1)] in immune checkpoint therapies. AXL is a receptor tyrosine kinase expressed in different types of cancer and in relation to resistance against various anticancer therapeutics due to poor clinical prognosis. AXL and its ligand, i.e., growth arrest-specific 6 (GAS6) proteins, are expressed on many cancer cells, and the GAS6/AXL pathway is reported to promote cancer cell proliferation, survival, migration, invasion, angiogenesis, and immune evasion. AXL is an attractive and novel therapeutic target for impairing tumor progression from immune cell contracts in the tumor microenvironment. The GAS6/AXL pathway is also of interest immunologically because it targets fewer antitumor immune responses. In effect, several targeted therapies are selective and nonselective for AXL, which are in preclinical and clinical development in multiple cancer types. Therefore, this review focuses on the role of the GAS6/AXL signaling pathway in triggering the immunosuppressive tumor microenvironment as immune evasion. This includes regulating its composition and activating T-cell exclusion with the immune-suppressive activity of regulatory T cells, which is related to one of the hallmarks of cancer survival. Finally, this article discusses the GAS6/AXL signaling pathway in the context of several immune responses such as NK cell activation, apoptosis, and tumor-specific immunity, especially PD-1/PDL-1 signaling.

scholarly journals Reliability of self-sampling for accurate assessment of respiratory virus viral and immunologic kinetics

2020 ◽  
Author(s):  
Alpana Waghmare ◽  
Elizabeth M. Krantz ◽  
Subhasish Baral ◽  
Emma Vasquez ◽  
Tillie Loeffelholz ◽  
...  
Keyword(s):  
Immune Responses ◽  
Respiratory Virus ◽  
Viral Infections ◽  
Immune Cell ◽  
Cell Of Origin ◽  
Virus Shedding ◽  
Viral Loads ◽  
Home Based ◽  
Cytokine Levels ◽  
Respiratory Viral Infections

AbstractThe SARS-CoV-2 pandemic demonstrates the need for accurate and convenient approaches to diagnose and therapeutically monitor respiratory viral infections. We demonstrated that self-sampling with foam swabs is well-tolerated and provides quantitative viral output concordant with flocked swabs. Using longitudinal home-based self-sampling, we demonstrate nasal cytokine levels correlate and cluster according to immune cell of origin. Periods of stable viral loads are followed by rapid elimination, which could be coupled with cytokine expansion and contraction using mathematical models. Nasal foam swab self-sampling at home provides a precise, mechanistic readout of respiratory virus shedding and local immune responses.

scholarly journals KIR gene content imputation from single-nucleotide polymorphisms in the Finnish population

PeerJ ◽  
2022 ◽  
Vol 10 ◽  
pp. e12692
Author(s):  
Jarmo Ritari ◽  
Kati Hyvärinen ◽  
Jukka Partanen ◽  
Satu Koskela
Keyword(s):  
Viral Infections ◽  
Nk Cell ◽  
Killer Cell ◽  
Cell Activity ◽  
Gene Copy Number ◽  
Human Leukocyte ◽  
Gene Content ◽  
Gene Copy ◽  
Nucleotide Polymorphisms ◽  
Kir Gene

The killer cell immunoglobulin-like receptor (KIR) gene cluster on chromosome 19 encodes cell surface glycoproteins that bind class I human leukocyte antigen (HLA) molecules as well as some other ligands. Through regulation of natural killer (NK) cell activity KIRs participate in tumour surveillance and clearing viral infections. KIR gene gene copy number variation associates with the outcome of transplantations and susceptibility to immune-mediated diseases. Inferring KIR gene content from genetic variant data is therefore desirable for immunogenetic analysis, particularly in the context of growing biobank genome data collections that rely on genotyping by microarray. Here we describe a stand-alone and freely available gene content imputation for 12 KIR genes. The models were trained using 807 Finnish biobank samples genotyped for 5900 KIR-region SNPs and analysed for KIR gene content with targeted sequencing. Cross-validation results demonstrate a high mean overall accuracy of 98.5% (95% CI [97.0–99.2]%) which compares favourably with previous methods including short-read sequencing based approaches.

Metabolic regulation of natural killer cells

2015 ◽  
Vol 43 (4) ◽  
pp. 758-762 ◽  
Author(s):  
David K. Finlay
Keyword(s):  
Immune Responses ◽  
Nk Cells ◽  
Natural Killer ◽  
Metabolic Regulation ◽  
Immune Cell ◽  
Nk Cell ◽  
Cellular Metabolism ◽  
T Cell Subsets ◽  
Immune Cell Subsets ◽  
Mtor Complex 1

Natural killer (NK) cells have key roles in anti-viral and anti-tumour immune responses. Recent research demonstrates that cellular metabolism is an important determinant for the function of pro-inflammatory immune cells, including activated NK cells. The mammalian target of rapamcyin (mTOR) complex 1 (mTORC1) has been identified as a key metabolic regulator that promotes glycolytic metabolism in multiple immune cell subsets. Glycolysis is integrally linked to pro-inflammatory immune responses such that activated NK cells and effector T-cell subsets are reliant on sufficient glucose availability for maximal effector function. This article will discuss the regulation of cellular metabolism in NK cells as compared with that of T lymphocytes and discuss the implications for NK cell responses to viral infection and cancer.

scholarly journals Hemocyte-hemocyte adhesion by granulocytes is associated with cellular immunity in the cricket, Gryllus bimaculatus

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Youngwoo Cho ◽  
Saeyoull Cho
Keyword(s):  
Immune Responses ◽  
Cellular Immunity ◽  
Post Infection ◽  
Plasma Membranes ◽  
Immune Cell ◽  
Gryllus Bimaculatus ◽  
Cellular Immune Responses ◽  
Size And Morphology ◽  
Cellular Immune ◽  
Unique Mechanism

AbstractIn this study, more than 1,000 cricket (Gryllus bimaculatus) hemocytes were classified based on their size and morphology. These hemocytes were classified into six types: granulocytes, plasmatocytes, prohemocytes, spherulocytes, coagulocytes, and oenocytoids. Hemocyte cultures was observed in real time to determine which hemocytes were associated with cellular immune responses against potential pathogens. Granulocytes were identified as the professional immune cell that mediates nodulation, encapsulation, and phagocytosis of pathogens. Granulocytes have been shown to actively produce various sticky nets (amoeba-like hairs and extracellular traps) from their plasma membranes that they use to gather other hemocytes and to implement cellular immune responses. The activation of lysosomes in granulocytes started at 4 h, peaked at 12 h, and returned to baseline by 24 h post-infection. At 48 h post-infection, cells could be found within the cytoplasm of granulocytes and reactivated lysosomes surrounding these cells were visible. This result seems to reflect a phenomenon in which necrotic granulocytes are removed by other healthy granulocytes. This unique mechanism of cellular immunity is therefore a way to efficiently and effectively remove pathogens and simultaneously maintain healthy hemocytes.

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