scholarly journals Learning from Bats to Escape from Potent or Severe Viral Infections

2021 ◽  
Author(s):  
Vijay Kumar
Keyword(s):  
Immune Response ◽  
Crucial Role ◽  
Viral Infections ◽  
Adaptive Immune Response ◽  
Severe Infection ◽  
Viral Pathogens ◽  
Adaptive Immune ◽  
Serious Infections ◽  
Animal Reservoirs

The COVID-19 pandemic that started in December 2019 in Wuhan city, China has created chaos all over the world with over 185 million infection cases and 4 million deaths world-wide. The pathogen behind COVID-19 has been identified as severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) that is more close to the previous SARS-CoV responsible for SARS epidemic 2002–2003. Although, SARS-CoV-2 also differs from SARS-CoV in many aspects as indicated by genetic studies. For example, SARS-CoV does not have a furin binding domain or site, whereas its presence in SARS-CoV-2 spike (S) protein increases its potential for infectivity. The horseshoe bats (Rhinolphus species) from China are considered as primary animal reservoirs for SARS-CoV and SARS-CoV-2. However, along with CoVs, bats also harbor many other viral pathogens (Ebola, Nipah, and Hendra viruses) without having serious infections. The bat physiology plays a crucial role in harboring these viruses along with adaptations to longevity and slow aging process. The immune system plays a crucial role in the clearance or establishment of the infection. Present chapter discusses different immunological aspects (innate immune response comprising the virus recognizing pattern recognition receptors (PRRs), type 1 interferon production, pro- and anti-inflammatory immune response, and adaptive immune response) that help bats to control viral infection without getting a severe infection as compared to other mammals, including humans.

Respiratory and gastrointestinal epithelial modulation of the immune response during viral infection

2011 ◽  
Vol 18 (1) ◽  
pp. 179-189 ◽  
Author(s):  
Paul M Fitch ◽  
Paul Henderson ◽  
Jürgen Schwarze
Keyword(s):  
Immune Response ◽  
Human Body ◽  
World Wide ◽  
Viral Infections ◽  
Adaptive Immune Response ◽  
Significant Morbidity ◽  
Viral Pathogens ◽  
Adaptive Immune ◽  
Adaptive Interface ◽  
Portal Of Entry

Respiratory and enteric viral infections cause significant morbidity and mortality world-wide and represent a major socio-economic burden. Many of these viruses have received unprecedented public and media interest in recent years. A popular public misconception is that viruses are a threat to which the human body has only limited defences. However, the majority of primary and secondary exposures to virus are asymptomatic or induce only minor symptoms. The mucosal epithelial surfaces are the main portal of entry for viral pathogens and are centrally involved in the initiation, maintenance and polarisation of the innate and adaptive immune response to infection. This review describes the defences employed by the epithelium of the respiratory and gastrointestinal tracts during viral infections with focus on epithelial modulation of the immune response at the innate/adaptive interface.

scholarly journals SARS-CoV-2 in severe COVID-19 induces a TGF-β-dominated chronic immune response that does not target itself

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Marta Ferreira-Gomes ◽  
Andrey Kruglov ◽  
Pawel Durek ◽  
Frederik Heinrich ◽  
Caroline Tizian ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Immune Reaction ◽  
Adaptive Immune Response ◽  
Gene Expression Signature ◽  
Spike Protein ◽  
Single Cell Level ◽  
Cell Level ◽  
Adaptive Immune

AbstractThe pathogenesis of severe COVID-19 reflects an inefficient immune reaction to SARS-CoV-2. Here we analyze, at the single cell level, plasmablasts egressed into the blood to study the dynamics of adaptive immune response in COVID-19 patients requiring intensive care. Before seroconversion in response to SARS-CoV-2 spike protein, peripheral plasmablasts display a type 1 interferon-induced gene expression signature; however, following seroconversion, plasmablasts lose this signature, express instead gene signatures induced by IL-21 and TGF-β, and produce mostly IgG1 and IgA1. In the sustained immune reaction from COVID-19 patients, plasmablasts shift to the expression of IgA2, thereby reflecting an instruction by TGF-β. Despite their continued presence in the blood, plasmablasts are not found in the lungs of deceased COVID-19 patients, nor does patient IgA2 binds to the dominant antigens of SARS-CoV-2. Our results thus suggest that, in severe COVID-19, SARS-CoV-2 triggers a chronic immune reaction that is instructed by TGF-β, and is distracted from itself.

scholarly journals The Innate Immune Responses of Colonic Epithelial Cells to Trichuris muris Are Similar in Mouse Strains That Develop a Type 1 or Type 2 Adaptive Immune Response

2006 ◽  
Vol 74 (11) ◽  
pp. 6280-6286 ◽  
Author(s):  
Matthew L. deSchoolmeester ◽  
Harinder Manku ◽  
Kathryn J. Else
Keyword(s):  
Immune Response ◽  
Epithelial Cells ◽  
Immune Responses ◽  
Adaptive Immune Response ◽  
Subsequent Development ◽  
Trichuris Muris ◽  
Adaptive Immune ◽  
Ifn Γ

ABSTRACT Trichuris muris resides in intimate contact with its host, burrowing within cecal epithelial cells. However, whether the enterocyte itself responds innately to T. muris is unknown. This study investigated for the first time whether colonic intestinal epithelial cells (IEC) produce cytokines or chemokines following T. muris infection and whether divergence of the innate response could explain differentially polarized adaptive immune responses in resistant and susceptible mice. Increased expression of mRNA for the proinflammatory cytokines gamma interferon (IFN-γ) and tumor necrosis factor and the chemokine CCL2 (MCP-1) were seen after infection of susceptible and resistant strains, with the only difference in expression being a delayed increase in CCL2 in BALB/c IEC. These increases were ablated in MyD88−/− mice, and NF-κB p65 was phosphorylated in response to T. muris excretory/secretory products in the epithelial cell line CMT-93, suggesting involvement of the MyD88-NF-κB signaling pathway in IEC cytokine expression. These data reveal that IEC respond innately to T. muris. However, the minor differences identified between resistant and susceptible mice are unlikely to underlie the subsequent development of a susceptible type 1 (IFN-γ-dominated) or resistant type 2 (interleukin-4 [IL-4]/IL-13-dominated) adaptive immune response.

scholarly journals Immune-Mediated Control of a Dormant Neurotropic RNA Virus Infection

2019 ◽  
Vol 93 (18) ◽  
Author(s):  
Katelyn D. Miller ◽  
Christine M. Matullo ◽  
Katelynn A. Milora ◽  
Riley M. Williams ◽  
Kevin J. O’Regan ◽  
...  
Keyword(s):  
Immune Response ◽  
Protein Synthesis ◽  
Measles Virus ◽  
Viral Infections ◽  
Acute Infection ◽  
Adaptive Immune Response ◽  
Viral Control ◽  
Cns Disease ◽  
Adaptive Immune ◽  
Immune Mediated

ABSTRACTGenomic material from many neurotropic RNA viruses (e.g., measles virus [MV], West Nile virus [WNV], Sindbis virus [SV], rabies virus [RV], and influenza A virus [IAV]) remains detectable in the mouse brain parenchyma long after resolution of the acute infection. The presence of these RNAs in the absence of overt central nervous system (CNS) disease has led to the suggestion that they are viral remnants, with little or no potential to reactivate. Here we show that MV RNA remains detectable in permissive mouse neurons long after challenge with MV and, moreover, that immunosuppression can cause RNA and protein synthesis to rebound, triggering neuropathogenesis months after acute viral control. Robust recrudescence of viral transcription and protein synthesis occurs after experimental depletion of cells of the adaptive immune response and is associated with a loss of T resident memory (Trm) lymphocytes within the brain. The disease associated with loss of immune control is distinct from that seen during the acute infection: immune cell-depleted, long-term-infected mice display severe gait and motor problems, in contrast to the wasting and lethal disease that occur during acute infection of immunodeficient hosts. These results illuminate the potential consequences of noncytolytic, immune-mediated viral control in the CNS and demonstrate that what were once considered “resolved” RNA viral infections may, in fact, induce diseases later in life that are distinct from those caused by acute infection.IMPORTANCEViral infections of neurons are often not cytopathic; thus, once-infected neurons survive, and viral RNAs can be detected long after apparent viral control. These RNAs are generally considered viral fossils, unlikely to contribute to central nervous system (CNS) disease. Using a mouse model of measles virus (MV) neuronal infection, we show that MV RNA is maintained in the CNS of infected mice long after acute control and in the absence of overt disease. Viral replication is suppressed by the adaptive immune response; when these immune cells are depleted, viral protein synthesis recurs, inducing a CNS disease that is distinct from that observed during acute infection. The studies presented here provide the basis for understanding how persistent RNA infections in the CNS are controlled by the host immune response, as well as the pathogenic consequences of noncytolytic viral control.

scholarly journals In severe COVID-19, SARS-CoV-2 induces a chronic, TGF-β-dominated adaptive immune response

2020 ◽  
Author(s):  
Marta Ferreira-Gomes ◽  
Andrey Kruglov ◽  
Pawel Durek ◽  
Frederik Heinrich ◽  
Caroline Tizian ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
B Cells ◽  
Immune Reaction ◽  
Adaptive Immune Response ◽  
Gene Expression Signature ◽  
Adaptive Immune ◽  
Activated B Cells ◽  
Peripheral B Cells

Here we have analyzed the dynamics of the adaptive immune response triggered by SARS-CoV-2 in severely affected COVID-19 patients, as reflected by activated B cells egressing into the blood, at the single cell level. Early on, before seroconversion in response to SARS-CoV-2 spike protein, activated peripheral B cells displayed a type 1 interferon-induced gene expression signature. After seroconversion, activated B cells lost this signature, expressed IL-21- and TGF-β-induced gene expression signatures, and mostly IgG1 and IgA1. In the sustained immune reaction of the COVID-19 patients, until day 59, activated peripheral B cells shifted to expression of IgA2, reflecting instruction by TGF-β. Despite the continued generation of activated B cells, those cells were not found in the lungs of deceased COVID-19 patients, nor did the IgA2 bind to dominant antigens of SARS-CoV-2. In severe COVID-19, SARS-CoV-2 thus triggers a chronic immune reaction distracted from itself and instructed by TGF-β.

The Immune Response to Respiratory Viruses: From Start to Memory

2021 ◽  
Vol 42 (06) ◽  
pp. 759-770
Author(s):  
Tom D.Y. Reijnders ◽  
Alex R. Schuurman ◽  
Tom van der Poll
Keyword(s):  
Immune Response ◽  
Viral Infections ◽  
Respiratory Viruses ◽  
Viral Pathogens ◽  
Adaptive Immune ◽  
Adaptive Immune Cells ◽  
Respiratory Viral Infections ◽  
Syncytial Virus ◽  
Destructive Inflammation ◽  
Systemic Memory

AbstractBiomedical research has long strived to improve our understanding of the immune response to respiratory viral infections, an effort that has become all the more important as we live through the consequences of a pandemic. The disease course of these infections is shaped in large part by the actions of various cells of the innate and adaptive immune systems. While these cells are crucial in clearing viral pathogens and establishing long-term immunity, their effector mechanisms may also escalate into excessive, tissue-destructive inflammation detrimental to the host. In this review, we describe the breadth of the immune response to infection with respiratory viruses such as influenza and respiratory syncytial virus. Throughout, we focus on the host rather than the pathogen and try to describe shared patterns in the host response to different viruses. We start with the local cells of the airways, onto the recruitment and activation of innate and adaptive immune cells, followed by the establishment of local and systemic memory cells key in protection against reinfection. We end by exploring how respiratory viral infections can predispose to bacterial superinfection.

scholarly journals Revealing the role of CD4+ T cells in viral immunity

2012 ◽  
Vol 209 (8) ◽  
pp. 1391-1395 ◽  
Author(s):  
Andrea J. Sant ◽  
Andrew McMichael
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Cd4 T Cells ◽  
Adaptive Immune Response ◽  
Neutralizing Antibody ◽  
Viral Immunity ◽  
Antigen Specificity ◽  
Viral Pathogens ◽  
Adaptive Immune

Protective immunity to chronic and acute viral infection relies on both the innate and adaptive immune response. Although neutralizing antibody production by B cells and cytotoxic activity of CD8+ T cells are well-accepted components of the adaptive immune response to viruses, identification of the specific role of CD4+ T cells in protection has been more challenging to establish. Delineating the contribution of CD4+ T cells has been complicated by their functional heterogeneity, breadth in antigen specificity, transient appearance in circulation, and sequestration in tissue sites of infection. In this minireview, we discuss recent progress in identifying the multiple roles of CD4+ T cells in orchestrating and mediating the immune responses against viral pathogens. We highlight several recent reports, including one published in this issue, that have employed comprehensive and sophisticated approaches to provide new evidence for CD4+ T cells as direct effectors in antiviral immunity.

scholarly journals Immune Responses Induced by mRNA Vaccination in Mice, Monkeys and Humans

Vaccines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 61
Author(s):  
Alberto Cagigi ◽  
Karin Loré
Keyword(s):  
Immune Response ◽  
Animal Models ◽  
Immune Responses ◽  
Viral Infections ◽  
Adaptive Immune Response ◽  
Adaptive Immune ◽  
Vaccine Trials ◽  
Concise Review

In this concise review, we summarize the concepts behind mRNA vaccination. We discuss the innate and adaptive immune response generated by mRNA vaccines in different animal models and in humans. We give examples of viral infections where mRNA vaccines have shown to induce potent responses and we discuss in more detail the recent SARS-CoV-2 mRNA vaccine trials in humans.

scholarly journals Long-term and short-term immunity to SARS-CoV-2: why it matters

2021 ◽  
Vol 42 (1) ◽  
pp. 34
Author(s):  
John Zaunders ◽  
Chansavath Phetsouphanh
Keyword(s):  
Immune Response ◽  
Adaptive Immunity ◽  
Viral Infections ◽  
Adaptive Immune Response ◽  
Recurrent Infection ◽  
Adaptive Immune System ◽  
Upper Respiratory Tract ◽  
Short Term ◽  
Adaptive Immune ◽  
Tract Infections

The adaptive immune system, regulated by CD4 T cells, is essential for control of many viral infections. Endemic coronavirus infections generally occur as short-term upper respiratory tract infections which in many cases appear to be cleared before adaptive immunity is fully involved, since adaptive immunity takes approximately 1.5–2 weeks to ramp up the response to a primary infection, or approximately 1 week for a recurrent infection. However, the adaptive immune response to SARS-CoV-2 infection will be critical to full recovery with minimal long-lasting effects, and to either prevention of recurrence of infection or at least reduced severity of symptoms. The detailed kinetics of this infection versus the dynamics of the immune response, including in vaccinated individuals, will largely determine these outcomes.

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