scholarly journals Longitudinal single-cell immune profiling revealed distinct innate immune response in asymptomatic COVID-19 patients

Author(s):  
Xiang-Na Zhao ◽  
Yue You ◽  
Guo-Lin Wang ◽  
Hui-Xia Gao ◽  
Xiao-Ming Cui ◽  
...  

SUMMARYRecent studies have characterized the single-cell immune landscape of host immune response of coronavirus disease 2019 (COVID-19), specifically focus on the severe condition. However, the immune response in mild or even asymptomatic patients remains unclear. Here, we performed longitudinal single-cell transcriptome sequencing and T cell/B cell receptor sequencing on 3 healthy donors and 10 COVID-19 patients with asymptomatic, moderate, and severe conditions. We found asymptomatic patients displayed distinct innate immune responses, including increased CD56briCD16− NK subset, which was nearly missing in severe condition and enrichment of a new Th2-like cell type/state expressing a ciliated cell marker. Unlike that in moderate condition, asymptomatic patients lacked clonal expansion of effector CD8+ T cells but had a robust effector CD4+ T cell clonal expansion, coincide with previously detected SARS-CoV-2-reactive CD4+ T cells in unexposed individuals. Moreover, NK and effector T cells in asymptomatic patients have upregulated cytokine related genes, such as IFNG and XCL2. Our data suggest early innate immune response and type I immunity may contribute to the asymptomatic phenotype in COVID-19 disease, which could in turn deepen our understanding of severe COVID-19 and guide early prediction and therapeutics.

2010 ◽  
Vol 84 (18) ◽  
pp. 9318-9325 ◽  
Author(s):  
Jincun Zhao ◽  
Jingxian Zhao ◽  
Stanley Perlman

ABSTRACT A dysregulated innate immune response and exuberant cytokine/chemokine expression are believed to be critical factors in the pathogenesis of severe acute respiratory syndrome (SARS), caused by a coronavirus (SARS-CoV). However, we recently showed that inefficient immune activation and a poor virus-specific T cell response underlie severe disease in SARS-CoV-infected mice. Here, we extend these results to show that virus-specific T cells, in the absence of activation of the innate immune response, were sufficient to significantly enhance survival and diminish clinical disease. We demonstrated that T cells are responsible for virus clearance, as intravenous adoptive transfer of SARS-CoV-immune splenocytes or in vitro-generated T cells to SCID or BALB/c mice enhanced survival and reduced virus titers in the lung. Enhancement of the number of virus-specific CD8 T cells by immunization with SARS-CoV peptide-pulsed dendritic cells also resulted in a robust T cell response, earlier virus clearance, and increased survival. These studies are the first to show that T cells play a crucial role in SARS-CoV clearance and that a suboptimal T cell response contributes to the pathological changes observed in SARS. They also provide a new approach to SARS vaccine design.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xiang-Na Zhao ◽  
Yue You ◽  
Xiao-Ming Cui ◽  
Hui-Xia Gao ◽  
Guo-Lin Wang ◽  
...  

AbstractWhile some individuals infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) present mild-to-severe disease, many SARS-CoV-2-infected individuals are asymptomatic. We sought to identify the distinction of immune response between asymptomatic and moderate patients. We performed single-cell transcriptome and T-cell/B-cell receptor (TCR/BCR) sequencing in 37 longitudinal collected peripheral blood mononuclear cell samples from asymptomatic, moderate, and severe patients with healthy controls. Asymptomatic patients displayed increased CD56briCD16− natural killer (NK) cells and upregulation of interferon-gamma in effector CD4+ and CD8+ T cells and NK cells. They showed more robust TCR clonal expansion, especially in effector CD4+ T cells, but lack strong BCR clonal expansion compared to moderate patients. Moreover, asymptomatic patients have lower interferon-stimulated genes (ISGs) expression in general but large interpatient variability, whereas moderate patients showed various magnitude and temporal dynamics of the ISGs expression across multiple cell populations but lower than a patient with severe disease. Our data provide evidence of different immune signatures to SARS-CoV-2 in asymptomatic infections.


2006 ◽  
Vol 203 (4) ◽  
pp. 933-940 ◽  
Author(s):  
Javier A. Carrero ◽  
Boris Calderon ◽  
Emil R. Unanue

Mice deficient in lymphocytes are more resistant than normal mice to Listeria monocytogenes infection during the early innate immune response. This paradox remains unresolved: lymphocytes are required for sterilizing immunity, but their presence during the early stage of the infection is not an asset and may even be detrimental. We found that lymphocyte-deficient mice, which showed limited apoptosis in infected organs, were resistant during the first four days of infection but became susceptible when engrafted with lymphocytes. Engraftment with lymphocytes from type I interferon receptor–deficient (IFN-αβR−/−) mice, which had reduced apoptosis, did not confer increased susceptibility to infection, even when the phagocytes were IFN-αβR+/+. The attenuation of innate immunity was due, in part, to the production of the antiinflammatory cytokine interleukin 10 by phagocytic cells after the apoptotic phase of the infection. Thus, immunodeficient mice were more resistant relative to normal mice because the latter went through a stage of lymphocyte apoptosis that was detrimental to the innate immune response. This is an example of a bacterial pathogen creating a cascade of events that leads to a permissive infective niche early during infection.


2005 ◽  
Vol 42 (8) ◽  
pp. 869-877 ◽  
Author(s):  
Peter L Smith ◽  
Giovanna Lombardi ◽  
Graham R Foster

2017 ◽  
Vol 19 (suppl_6) ◽  
pp. vi115-vi116 ◽  
Author(s):  
Sarah R Klein ◽  
Maria Carmela Speranza ◽  
Prafulla C Gokhale ◽  
Margaret K Wilkens ◽  
Kristen L Jones ◽  
...  

2021 ◽  
Author(s):  
Tai L Ng ◽  
Erika J Olson ◽  
Tae Yeon Yoo ◽  
H. Sloane Weiss ◽  
Yukiye Koide ◽  
...  

Suppression of the host innate immune response is a critical aspect of viral replication. Upon infection, viruses may introduce one or more proteins that inhibit key immune pathways, such as the type I interferon pathway. However, the ability to predict and evaluate viral protein bioactivity on targeted pathways remains challenging and is typically done on a single virus/gene basis. Here, we present a medium-throughput high-content cell-based assay to reveal the immunosuppressive effects of viral proteins. To test the predictive power of our approach, we developed a library of 800 genes encoding known, predicted, and uncharacterized human viral genes. We find that previously known immune suppressors from numerous viral families such as Picornaviridae and Flaviviridae recorded positive responses. These include a number of viral proteases for which we further confirmed that innate immune suppression depends on protease activity. A class of predicted inhibitors encoded by Rhabdoviridae viruses was demonstrated to block nuclear transport, and several previously uncharacterized proteins from uncultivated viruses were shown to inhibit nuclear transport of the transcription factors NF-kB and IRF3. We propose that this pathway-based assay, together with early sequencing, gene synthesis, and viral infection studies, could partly serve as the basis for rapid in vitro characterization of novel viral proteins.


2021 ◽  
Author(s):  
Raphaël Jami ◽  
Emilie Mérour ◽  
Julie Bernard ◽  
Annie Lamoureux ◽  
Jean K. Millet ◽  
...  

Salmonid alphavirus (SAV) is an atypical alphavirus, which has a considerable impact on salmon and trout farms. Unlike other alphaviruses such as the chikungunya virus, SAV is transmitted without an arthropod vector, and does not cause cell shut-off during infection. The mechanisms by which SAV escapes the host immune system remain unknown. By studying the role of SAV proteins on the RIG-I signaling cascade, the first line of defense of the immune system during infection, we demonstrated that non-structural protein 2 (nsP2) effectively blocks the induction of type I interferon (IFN). This inhibition, independent of the protease activity carried by nsP2, occurs downstream of IRF3 which is the transcription factor allowing the activation of the IFN promoter and its expression. The inhibitory effect of nsP2 on the RIG-I pathway depends on the localization of nsP2 in the host cell nucleus which is linked to two nuclear localization sequences (NLS) located in its C-terminal part. The C-terminal domain of nsP2 by itself is sufficient and necessary to block IFN induction. Mutation of the NLS of nsP2 is deleterious to the virus. Finally, nsP2 does not interact with IRF3, indicating that its action is possible through a targeted interaction within discrete areas of chromatin, as suggested by its punctate distribution observed in the nucleus. These results therefore demonstrate a major role for nsP2 in the control by SAV of the host cell’s innate immune response. Importance The global consumption of fish continues to rise and the future demand cannot be met by capture fisheries alone due to limited stocks of wild fish. Aquaculture is currently the world’s fastest growing food production sector with an annual growth rate of 6-8 %. Recurrent outbreaks of SAV result in significant economic losses with serious environmental consequences on wild stocks. While the clinical and pathological signs of SAV infection are fairly well known, the molecular mechanisms involved are poorly described. In the present study, we focus on the non-structural protein nsP2 and characterize a specific domain containing nuclear localization sequences that are critical for the inhibition of the host innate immune response mediated by the RIG-I pathway.


Author(s):  
Dalia Cicily Kattiparambil Dixon ◽  
Chameli Ratan ◽  
Bhagyalakshmi Nair ◽  
Sabitha Mangalath ◽  
Rachy Abraham ◽  
...  

: Innate immunity is the first line of defence elicited by the host immune system to fight against invading pathogens such as viruses and bacteria. From this elementary immune response, the more complex antigen-specific adaptive responses are recruited to provide a long-lasting memory against the pathogens. Innate immunity gets activated when the host cell utilizes a diverse set of receptors known as pattern recognition receptors (PRR) to recognize the viruses that have penetrated the host and respond with cellular processes like complement system, phagocytosis, cytokine release and inflammation and destruction of NK cells. Viral RNA or DNA or viral intermediate products are recognized by receptors like toll-like receptors(TLRs), nucleotide oligomerization domain(NOD)-like receptors (NLRs) and retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) thereby, inducing type I interferon response (IFN) and other proinflammatory cytokines in infected cells or other immune cells. But certain viruses can evade the host innate immune response to replicate efficiently, triggering the spread of the viral infection. The present review describes the similarity in the mechanism chosen by viruses from different families -HIV, SARS-CoV2 and Nipah viruses to evade the innate immune response and how efficiently they establish the infection in the host. The review also addresses the stages of developments of various vaccines against these viral diseases and the challenges encountered by the researchers during vaccine development.


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