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  1. Article ; Online: Protective and pathogenic roles for mast cells during viral infections.

    Rathore, Abhay Ps / St John, Ashley L

    Current opinion in immunology

    2020  Volume 66, Page(s) 74–81

    Abstract: Mast cells (MCs) are long-lived immune cells. They are armed with preformed mediators within granules that can be instantaneously released in response to an invading pathogen, including certain viruses. At the skin and mucosae, they initiate innate ... ...

    Abstract Mast cells (MCs) are long-lived immune cells. They are armed with preformed mediators within granules that can be instantaneously released in response to an invading pathogen, including certain viruses. At the skin and mucosae, they initiate innate immune responses and promote the development of adaptive immune responses, through cellular recruitment or antigen presentation. However, systemic MC activation may promote immune pathologies through their vasoactive proteases and biogenic amines. Recently, MC products were identified to contribute to pathologies associated with viral hemorrhagic fever, such vascular leakage and thrombocytopenia. Similar associations of MCs with disease severity have been noted for certain respiratory viral pathogens. Here we discuss the specific MC responses to viruses and their influences on functional immune outcomes during infection.
    MeSH term(s) Animals ; Humans ; Immunity, Innate/immunology ; Mast Cells/immunology ; Virus Diseases/immunology
    Keywords covid19
    Language English
    Publishing date 2020-06-18
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 1035767-1
    ISSN 1879-0372 ; 0952-7915
    ISSN (online) 1879-0372
    ISSN 0952-7915
    DOI 10.1016/j.coi.2020.05.003
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Risk factors and biomarkers of severe dengue.

    Rathore, Abhay Ps / Farouk, Farouk S / St John, Ashley L

    Current opinion in virology

    2020  Volume 43, Page(s) 1–8

    Abstract: Dengue virus infects several million people each year. Although usually a self-limiting disease, some patients can develop life-threatening severe complications, characterized by plasma leakage, hemorrhaging, and shock. The signs and symptoms of severe ... ...

    Abstract Dengue virus infects several million people each year. Although usually a self-limiting disease, some patients can develop life-threatening severe complications, characterized by plasma leakage, hemorrhaging, and shock. The signs and symptoms of severe disease usually arise late in the disease course when patients are recovering and fever has subsided, making it difficult to predict. Efforts are underway to identify risk factors and biomarkers that can accurately predict disease severity in the acute febrile phase of the disease, facilitating early intervention and treatment strategies for those at greatest risk. In this review we discuss recent advancements in identifying risk factors and biomarkers for the prognosis of severe dengue.
    MeSH term(s) Animals ; Biomarkers/blood ; Dengue Virus/genetics ; Dengue Virus/physiology ; Humans ; Prognosis ; Risk Factors ; Severe Dengue/blood ; Severe Dengue/diagnosis ; Severe Dengue/epidemiology ; Severe Dengue/virology ; Severity of Illness Index
    Chemical Substances Biomarkers
    Language English
    Publishing date 2020-07-17
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 2611378-8
    ISSN 1879-6265 ; 1879-6257
    ISSN (online) 1879-6265
    ISSN 1879-6257
    DOI 10.1016/j.coviro.2020.06.008
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Promises and challenges of mucosal COVID-19 vaccines

    Rathore, Abhay P.S. / St. John, Ashley L.

    Vaccine. 2023 Apr. 10,

    2023  

    Abstract: Coronavirus disease-2019 (COVID-19) is an ongoing pandemic caused by the newly emerged virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, COVID-19 vaccines are given intramuscularly and they have been shown to evoke systemic ... ...

    Abstract Coronavirus disease-2019 (COVID-19) is an ongoing pandemic caused by the newly emerged virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, COVID-19 vaccines are given intramuscularly and they have been shown to evoke systemic immune responses that are highly efficacious towards preventing severe disease and death. However, vaccine-induced immunity wanes within a short time, and booster doses are currently recommended. Furthermore, current vaccine formulations do not adequately restrict virus infection at the mucosal sites, such as in the nasopharyngeal tract and, therefore, have limited capacity to block virus transmission. With these challenges in mind, several mucosal vaccines are currently being developed with the aim of inducing long-lasting protective immune responses at the mucosal sites where SARS-COV-2 infection begins. Past successes in mucosal vaccinations underscore the potential of these developmental stage SARS-CoV-2 vaccines to reduce disease burden, if not eliminate it altogether. Here, we discuss immune responses that are triggered at the mucosal sites and recent advances in our understanding of mucosal responses induced by SARS-CoV-2 infection and current COVID-19 vaccines. We also highlight several mucosal SARS-COV-2 vaccine formulations that are currently being developed or tested for human use and discuss potential challenges to mucosal vaccination.
    Keywords COVID-19 infection ; Severe acute respiratory syndrome coronavirus 2 ; burden of disease ; death ; disease severity ; humans ; immunity ; pandemic ; vaccination ; vaccines ; virus transmission ; viruses
    Language English
    Dates of publication 2023-0410
    Publishing place Elsevier Ltd
    Document type Article ; Online
    Note Pre-press version ; Use and reproduction
    ZDB-ID 605674-x
    ISSN 1873-2518 ; 0264-410X
    ISSN (online) 1873-2518
    ISSN 0264-410X
    DOI 10.1016/j.vaccine.2023.04.013
    Database NAL-Catalogue (AGRICOLA)

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  4. Article ; Online: Mast cell activation in lungs during SARS-CoV-2 infection associated with lung pathology and severe COVID-19.

    Tan, Janessa Yj / Anderson, Danielle E / Rathore, Abhay Ps / O'Neill, Aled / Mantri, Chinmay Kumar / Saron, Wilfried Aa / Lee, Cheryl Qe / Cui, Chu Wern / Kang, Adrian Ez / Foo, Randy / Kalimuddin, Shirin / Low, Jenny G / Ho, Lena / Tambyah, Paul / Burke, Thomas W / Woods, Christopher W / Chan, Kuan Rong / Karhausen, Jörn / St John, Ashley L

    The Journal of clinical investigation

    2023  Volume 133, Issue 19

    Abstract: Lung inflammation is a hallmark of Coronavirus disease 2019 (COVID-19) in patients who are severely ill, and the pathophysiology of disease is thought to be immune mediated. Mast cells (MCs) are polyfunctional immune cells present in the airways, where ... ...

    Abstract Lung inflammation is a hallmark of Coronavirus disease 2019 (COVID-19) in patients who are severely ill, and the pathophysiology of disease is thought to be immune mediated. Mast cells (MCs) are polyfunctional immune cells present in the airways, where they respond to certain viruses and allergens and often promote inflammation. We observed widespread degranulation of MCs during acute and unresolved airway inflammation in SARS-CoV-2-infected mice and nonhuman primates. Using a mouse model of MC deficiency, MC-dependent interstitial pneumonitis, hemorrhaging, and edema in the lung were observed during SARS-CoV-2 infection. In humans, transcriptional changes in patients requiring oxygen supplementation also implicated cells with a MC phenotype in severe disease. MC activation in humans was confirmed through detection of MC-specific proteases, including chymase, the levels of which were significantly correlated with disease severity and with biomarkers of vascular dysregulation. These results support the involvement of MCs in lung tissue damage during SARS-CoV-2 infection in animal models and the association of MC activation with severe COVID-19 in humans, suggesting potential strategies for intervention.
    MeSH term(s) Humans ; Animals ; COVID-19/pathology ; Mast Cells/pathology ; SARS-CoV-2 ; Lung/pathology ; Inflammation/pathology
    Language English
    Publishing date 2023-10-02
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 3067-3
    ISSN 1558-8238 ; 0021-9738
    ISSN (online) 1558-8238
    ISSN 0021-9738
    DOI 10.1172/JCI149834
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Dengue virus-elicited tryptase induces endothelial permeability and shock.

    Rathore, Abhay Ps / Mantri, Chinmay Kumar / Aman, Siti Ab / Syenina, Ayesa / Ooi, Justin / Jagaraj, Cyril J / Goh, Chi Ching / Tissera, Hasitha / Wilder-Smith, Annelies / Ng, Lai Guan / Gubler, Duane J / St John, Ashley L

    The Journal of clinical investigation

    2019  Volume 129, Issue 10, Page(s) 4180–4193

    Abstract: Dengue virus (DENV) infection causes a characteristic pathology in humans involving dysregulation of the vascular system. In some patients with dengue hemorrhagic fever (DHF), vascular pathology can become severe, resulting in extensive microvascular ... ...

    Abstract Dengue virus (DENV) infection causes a characteristic pathology in humans involving dysregulation of the vascular system. In some patients with dengue hemorrhagic fever (DHF), vascular pathology can become severe, resulting in extensive microvascular permeability and plasma leakage into tissues and organs. Mast cells (MCs), which line blood vessels and regulate vascular function, are able to detect DENV in vivo and promote vascular leakage. Here, we identified that a MC-derived protease, tryptase, is consequential for promoting vascular permeability during DENV infection, through inducing breakdown of endothelial cell tight junctions. Injected tryptase alone was sufficient to induce plasma loss from the circulation and hypovolemic shock in animals. A potent tryptase inhibitor, nafamostat mesylate, blocked DENV-induced vascular leakage in vivo. Importantly, in two independent human dengue cohorts, tryptase levels correlated with the grade of DHF severity. This study defines an immune mechanism by which DENV can induce vascular pathology and shock.
    MeSH term(s) Animals ; Capillary Permeability ; Cell Line ; Dengue/drug therapy ; Dengue/enzymology ; Dengue/pathology ; Dengue/virology ; Dengue Virus/metabolism ; Endothelium, Vascular/enzymology ; Endothelium, Vascular/pathology ; Endothelium, Vascular/virology ; Guanidines/pharmacology ; Humans ; Mast Cells/enzymology ; Mast Cells/pathology ; Mast Cells/virology ; Mice ; Shock/drug therapy ; Shock/enzymology ; Shock/pathology ; Shock/virology ; Tight Junctions/metabolism ; Tight Junctions/pathology ; Tryptases/antagonists & inhibitors ; Tryptases/genetics ; Tryptases/metabolism
    Chemical Substances Guanidines ; Tryptases (EC 3.4.21.59) ; nafamostat (Y25LQ0H97D)
    Language English
    Publishing date 2019-07-02
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 3067-3
    ISSN 1558-8238 ; 0021-9738
    ISSN (online) 1558-8238
    ISSN 0021-9738
    DOI 10.1172/JCI128426
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Mucosal SARS-CoV-2 vaccination of rodents elicits superior systemic T central memory function and cross-neutralising antibodies against variants of concernResearch in context

    Aled O’Neill / Chinmay Kumar Mantri / Chee Wah Tan / Wilfried A.A. Saron / Santhosh Kambaiah Nagaraj / Monica Palanichamy Kala / Christy Margarat Joy / Abhay P.S. Rathore / Shashank Tripathi / Lin-Fa Wang / Ashley L. St. John

    EBioMedicine, Vol 99, Iss , Pp 104924- (2024)

    1481  

    Abstract: Summary: Background: COVID-19 vaccines used in humans are highly effective in limiting disease and death caused by the SARS-CoV-2 virus, yet improved vaccines that provide greater protection at mucosal surfaces, which could reduce break-through ... ...

    Abstract Summary: Background: COVID-19 vaccines used in humans are highly effective in limiting disease and death caused by the SARS-CoV-2 virus, yet improved vaccines that provide greater protection at mucosal surfaces, which could reduce break-through infections and subsequent transmission, are still needed. Methods: Here we tested an intranasal (I.N.) vaccination with the receptor binding domain of Spike antigen of SARS-CoV-2 (S-RBD) in combination with the mucosal adjuvant mastoparan-7 compared with the sub-cutaneous (S.C.) route, adjuvanted by either M7 or the gold-standard adjuvant, alum, in mice, for immunological read-outs. The same formulation delivered I.N. or S.C. was tested in hamsters to assess efficacy. Findings: I.N. vaccination improved systemic T cell responses compared to an equivalent dose of antigen delivered S.C. and T cell phenotypes induced by I.N. vaccine administration included enhanced polyfunctionality (combined IFN-γ and TNF expression) and greater numbers of T central memory (TCM) cells. These phenotypes were T cell-intrinsic and could be recalled in the lungs and/or brachial LNs upon antigen challenge after adoptive T cell transfer to naïve recipients. Furthermore, mucosal vaccination induced antibody responses that were similarly effective in neutralising the binding of the parental strain of S-RBD to its ACE2 receptor, but showed greater cross-neutralising capacity against multiple variants of concern (VOC), compared to S.C. vaccination. I.N. vaccination provided significant protection from lung pathology compared to unvaccinated animals upon challenge with homologous and heterologous SARS-CoV-2 strains in a hamster model. Interpretation: These results highlight the role of nasal vaccine administration in imprinting an immune profile associated with long-term T cell retention and diversified neutralising antibody responses, which could be applied to improve vaccines for COVID-19 and other infectious diseases. Funding: This study was funded by Duke-NUS Medical School, the Singapore Ministry ...
    Keywords Mucosal vaccine ; T cell ; SARS-CoV-2 ; COVID-19 ; Medicine ; R ; Medicine (General) ; R5-920
    Subject code 570
    Language English
    Publishing date 2024-01-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Contributions of mast cells and vasoactive products, leukotrienes and chymase, to dengue virus-induced vascular leakage

    Ashley L St John / Abhay PS Rathore / Bhuvanakantham Raghavan / Mah-Lee Ng / Soman N Abraham

    eLife, Vol

    2013  Volume 2

    Abstract: Dengue Virus (DENV), a flavivirus spread by mosquito vectors, can cause vascular leakage and hemorrhaging. However, the processes that underlie increased vascular permeability and pathological plasma leakage during viral hemorrhagic fevers are largely ... ...

    Abstract Dengue Virus (DENV), a flavivirus spread by mosquito vectors, can cause vascular leakage and hemorrhaging. However, the processes that underlie increased vascular permeability and pathological plasma leakage during viral hemorrhagic fevers are largely unknown. Mast cells (MCs) are activated in vivo during DENV infection, and we show that this elevates systemic levels of their vasoactive products, including chymase, and promotes vascular leakage. Treatment of infected animals with MC-stabilizing drugs or a leukotriene receptor antagonist restores vascular integrity during experimental DENV infection. Validation of these findings using human clinical samples revealed a direct correlation between MC activation and DENV disease severity. In humans, the MC-specific product, chymase, is a predictive biomarker distinguishing dengue fever (DF) and dengue hemorrhagic fever (DHF). Additionally, our findings reveal MCs as potential therapeutic targets to prevent DENV-induced vasculopathy, suggesting MC-stabilizing drugs should be evaluated for their effectiveness in improving disease outcomes during viral hemorrhagic fevers.
    Keywords mast cell ; vascular leakage ; dengue virus ; chymase ; leukotrienes ; Medicine ; R ; Science ; Q ; Biology (General) ; QH301-705.5
    Subject code 610
    Language English
    Publishing date 2013-04-01T00:00:00Z
    Publisher eLife Sciences Publications Ltd
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: Mucosal vaccination for SARS-CoV-2 elicits superior systemic T central memory function and cross-neutralizing antibodies against variants of concern

    ONeill, Aled / Kala, Monica Palanichamy / Tan, Chee Wah / Saron, Wilfried A. A. / Mantri, Chinmay Kumar / Rathore, Abhay P.S. / Wang, Lin-Fa / St. John, Ashley L.

    bioRxiv

    Abstract: COVID-19 vaccines used in humans are highly effective in limiting disease and death caused by the SARS-CoV-2 virus, yet improved vaccines that provide greater protection at mucosal surfaces, which could reduce break-through infections and subsequent ... ...

    Abstract COVID-19 vaccines used in humans are highly effective in limiting disease and death caused by the SARS-CoV-2 virus, yet improved vaccines that provide greater protection at mucosal surfaces, which could reduce break-through infections and subsequent transmission, are still needed. Here we show that intranasal (I.N.) vaccination with the receptor binding domain of Spike antigen of SARS-CoV-2 (S-RBD) in combination with the mucosal adjuvant mastoparan-7 improved systemic T cell responses compared to an equivalent dose of antigen delivered by the sub-cutaneous (S.C.) route, adjuvanted by either M7 or the gold-standard adjuvant, alum. T cell phenotypes induced by I.N. vaccine administration included enhanced polyfunctionality (combined IFN and TNF expression) and greater numbers of T central memory (TCM) cells. These phenotypes were T cell-intrinsic and could be recalled in the lungs and/or brachial LNs upon antigen challenge after adoptive T cell transfer to naive recipients. Furthermore, mucosal vaccination induced antibody responses that were similarly effective in neutralizing the binding of the parental strain of S-RBD to its ACE2 receptor, but showed greater cross-neutralizing capacity against multiple variants of concern (VOC), compared to S.C. vaccination. These results highlight the role of nasal vaccine administration in imprinting an immune profile associated with long-term T cell retention and diversified neutralizing antibody responses, which could be applied to improve vaccines for COVID-19 and other infectious diseases.
    Keywords covid19
    Language English
    Publishing date 2022-09-09
    Publisher Cold Spring Harbor Laboratory
    Document type Article ; Online
    DOI 10.1101/2022.09.09.507250
    Database COVID19

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  9. Article ; Online: Mast cell activation in lungs during SARS-CoV-2 infection associated with lung pathology and severe COVID-19

    Janessa Y.J. Tan / Danielle E. Anderson / Abhay P.S. Rathore / Aled O’Neill / Chinmay Kumar Mantri / Wilfried A.A. Saron / Cheryl Q.E. Lee / Chu Wern Cui / Adrian E.Z. Kang / Randy Foo / Shirin Kalimuddin / Jenny G. Low / Lena Ho / Paul Tambyah / Thomas W. Burke / Christopher W. Woods / Kuan Rong Chan / Jörn Karhausen / Ashley L. St. John

    The Journal of Clinical Investigation, Vol 133, Iss

    2023  Volume 19

    Abstract: Lung inflammation is a hallmark of Coronavirus disease 2019 (COVID-19) in patients who are severely ill, and the pathophysiology of disease is thought to be immune mediated. Mast cells (MCs) are polyfunctional immune cells present in the airways, where ... ...

    Abstract Lung inflammation is a hallmark of Coronavirus disease 2019 (COVID-19) in patients who are severely ill, and the pathophysiology of disease is thought to be immune mediated. Mast cells (MCs) are polyfunctional immune cells present in the airways, where they respond to certain viruses and allergens and often promote inflammation. We observed widespread degranulation of MCs during acute and unresolved airway inflammation in SARS-CoV-2-infected mice and nonhuman primates. Using a mouse model of MC deficiency, MC-dependent interstitial pneumonitis, hemorrhaging, and edema in the lung were observed during SARS-CoV-2 infection. In humans, transcriptional changes in patients requiring oxygen supplementation also implicated cells with a MC phenotype in severe disease. MC activation in humans was confirmed through detection of MC-specific proteases, including chymase, the levels of which were significantly correlated with disease severity and with biomarkers of vascular dysregulation. These results support the involvement of MCs in lung tissue damage during SARS-CoV-2 infection in animal models and the association of MC activation with severe COVID-19 in humans, suggesting potential strategies for intervention.
    Keywords COVID-19 ; Medicine ; R
    Subject code 610
    Language English
    Publishing date 2023-10-01T00:00:00Z
    Publisher American Society for Clinical Investigation
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Signatures of mast cell activation are associated with severe COVID-19

    Tan, Janessa / Anderson, Danielle / Rathore, Abhay P.S. / O'Neill, Aled / Mantri, Chinmay Kumar / Saron, Wilfried A.A. / Lee, Cheryl / Chu, Wern Chui / Kang, Adrian / Foo, Randy / Kalimuddin, Shirin / Low, Jenny / Ho, Lena / Tambyah, Paul / Burke, Thomas W. / Woods, Christopher W. / Chan, Kuan Rong / Karhausen, Joern / St John, Ashley L.

    medRxiv

    Abstract: Lung inflammation is a hallmark of Coronavirus disease 2019 (COVID-19) in severely ill patients and the pathophysiology of disease is thought to be immune-mediated. Mast cells (MCs) are polyfunctional immune cells present in the airways, where they ... ...

    Abstract Lung inflammation is a hallmark of Coronavirus disease 2019 (COVID-19) in severely ill patients and the pathophysiology of disease is thought to be immune-mediated. Mast cells (MCs) are polyfunctional immune cells present in the airways, where they respond to certain viruses and allergens, often promoting inflammation. We observed widespread degranulation of MCs during acute and unresolved airway inflammation in SARS-CoV-2-infected mice and non-human primates. In humans, transcriptional changes in patients requiring oxygen supplementation also implicated cells with a MC phenotype. MC activation in humans was confirmed, through detection of the MC-specific protease, chymase, levels of which were significantly correlated with disease severity. These results support the association of MC activation with severe COVID-19, suggesting potential strategies for intervention.
    Keywords covid19
    Language English
    Publishing date 2021-06-01
    Publisher Cold Spring Harbor Laboratory Press
    Document type Article ; Online
    DOI 10.1101/2021.05.31.21255594
    Database COVID19

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