Browsing by keyword "Viral infection"
Now showing items 1-6 of 6
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A cross-reactive human IgA monoclonal antibody blocks SARS-CoV-2 spike-ACE2 interactionCOVID-19 caused by SARS-CoV-2 has become a global pandemic requiring the development of interventions for the prevention or treatment to curtail mortality and morbidity. No vaccine to boost mucosal immunity, or as a therapeutic, has yet been developed to SARS-CoV-2. In this study, we discover and characterize a cross-reactive human IgA monoclonal antibody, MAb362. MAb362 binds to both SARS-CoV and SARS-CoV-2 spike proteins and competitively blocks ACE2 receptor binding, by overlapping the ACE2 structural binding epitope. Furthermore, MAb362 IgA neutralizes both pseudotyped SARS-CoV and SARS-CoV-2 in 293 cells expressing ACE2. When converted to secretory IgA, MAb326 also neutralizes authentic SARS-CoV-2 virus while the IgG isotype shows no neutralization. Our results suggest that SARS-CoV-2 specific IgA antibodies, such as MAb362, may provide effective immunity against SARS-CoV-2 by inducing mucosal immunity within the respiratory system, a potentially critical feature of an effective vaccine.
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Defining the substrate envelope of SARS-CoV-2 main protease to predict and avoid drug resistanceCoronaviruses can evolve and spread rapidly to cause severe disease morbidity and mortality, as exemplified by SARS-CoV-2 variants of the COVID-19 pandemic. Although currently available vaccines remain mostly effective against SARS-CoV-2 variants, additional treatment strategies are needed. Inhibitors that target essential viral enzymes, such as proteases and polymerases, represent key classes of antivirals. However, clinical use of antiviral therapies inevitably leads to emergence of drug resistance. In this study we implemented a strategy to pre-emptively address drug resistance to protease inhibitors targeting the main protease (M(pro)) of SARS-CoV-2, an essential enzyme that promotes viral maturation. We solved nine high-resolution cocrystal structures of SARS-CoV-2 M(pro) bound to substrate peptides and six structures with cleavage products. These structures enabled us to define the substrate envelope of M(pro), map the critical recognition elements, and identify evolutionarily vulnerable sites that may be susceptible to resistance mutations that would compromise binding of the newly developed M(pro) inhibitors. Our results suggest strategies for developing robust inhibitors against SARS-CoV-2 that will retain longer-lasting efficacy against this evolving viral pathogen.
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Early-stage COVID-19 pandemic observations on pulmonary embolism using nationwide multi-institutional data harvestingWe introduce a multi-institutional data harvesting (MIDH) method for longitudinal observation of medical imaging utilization and reporting. By tracking both large-scale utilization and clinical imaging results data, the MIDH approach is targeted at measuring surrogates for important disease-related observational quantities over time. To quantitatively investigate its clinical applicability, we performed a retrospective multi-institutional study encompassing 13 healthcare systems throughout the United States before and after the 2020 COVID-19 pandemic. Using repurposed software infrastructure of a commercial AI-based image analysis service, we harvested data on medical imaging service requests and radiology reports for 40,037 computed tomography pulmonary angiograms (CTPA) to evaluate for pulmonary embolism (PE). Specifically, we compared two 70-day observational periods, namely (i) a pre-pandemic control period from 11/25/2019 through 2/2/2020, and (ii) a period during the early COVID-19 pandemic from 3/8/2020 through 5/16/2020. Natural language processing (NLP) on final radiology reports served as the ground truth for identifying positive PE cases, where we found an NLP accuracy of 98% for classifying radiology reports as positive or negative for PE based on a manual review of 2,400 radiology reports. Fewer CTPA exams were performed during the early COVID-19 pandemic than during the pre-pandemic period (9806 vs. 12,106). However, the PE positivity rate was significantly higher (11.6 vs. 9.9%, p < 10-4) with an excess of 92 PE cases during the early COVID-19 outbreak, i.e., ~1.3 daily PE cases more than statistically expected. Our results suggest that MIDH can contribute value as an exploratory tool, aiming at a better understanding of pandemic-related effects on healthcare.
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Interleukin-36beta provides protection against HSV-1 infection, but does not modulate initiation of adaptive immune responsesInterleukin-36 (IL-36) represents three cytokines, IL-36alpha, IL-36beta and IL-36gamma, which bind to the same receptor, IL-1RL2; however, their physiological function(s) remain poorly understood. Here, the role of IL-36 in immunity against HSV-1 was examined using the flank skin infection mouse model. Expression analyses revealed increased levels of IL-36alpha and IL-36beta mRNA in infected skin, while constitutive IL-36gamma levels remained largely unchanged. In human keratinocytes, IL-36alpha mRNA was induced by HSV-1, while IL-1beta and TNFalpha increased all three IL-36 mRNAs. The dominant alternative splice variant of human IL-36beta mRNA was isoform 2, which is the ortholog of the known mouse IL-36beta mRNA. Mice deficient in IL-36beta, but not IL-36alpha or IL-36gamma, succumbed more frequently to HSV-1 infection than wild type mice. Furthermore, IL-36beta(-/-) mice developed larger zosteriform skin lesions along infected neurons. Levels of HSV-1 specific antibodies, CD8(+) cells and IFNgamma-producing CD4(+) cells were statistically equal in wild type and IL-36beta(-/-) mice, suggesting similar initiation of adaptive immunity in the two strains. This correlated with the time at which HSV-1 genome and mRNA levels in primary skin lesions started to decline in both wild type and IL-36beta(-/-) mice. Our data indicate that IL-36beta has previously unrecognized functions protective against HSV-1 infection.
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Leveraging the Massachusetts perinatal quality collaborative to address the COVID-19 pandemic among diverse populationsOBJECTIVE: We leveraged the Massachusetts perinatal quality collaborative (PQC) to address the COVID-19 pandemic. Our goals were to: (1) implement perinatal practices thought to reduce mother-to-infant SARS-CoV-2 transmission while limiting disruption of health-promoting practices and (2) do so without inequities attributable to race/ethnicity, language status, and social vulnerability. METHODS: Main outcomes were cesarean and preterm delivery, rooming-in, and breastfeeding. We examined changes over time overall and according to race/ethnicity, language status, and social vulnerability from 03/20-07/20 at 11 hospitals. RESULTS: Of 255 mothers with SARS-CoV-2, 67% were black or Hispanic and 47% were non-English speaking. Cesarean decreased (49% to 35%), while rooming-in (55% to 86%) and breastfeeding (53% to 72%) increased. These changes did not differ by race/ethnicity, language, or social vulnerability. CONCLUSIONS: Leveraging the Massachusetts PQC led to rapid changes in perinatal care during the COVID-19 crisis in a short time, representing a novel use of statewide PQC structures.
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Toll-like receptor-mediated innate immunity against herpesviridae infection: a current perspective on viral infection signaling pathwaysBACKGROUND: In the past decades, researchers have demonstrated the critical role of Toll-like receptors (TLRs) in the innate immune system. They recognize viral components and trigger immune signal cascades to subsequently promote the activation of the immune system. MAIN BODY: Herpesviridae family members trigger TLRs to elicit cytokines in the process of infection to activate antiviral innate immune responses in host cells. This review aims to clarify the role of TLRs in the innate immunity defense against herpesviridae, and systematically describes the processes of TLR actions and herpesviridae recognition as well as the signal transduction pathways involved. CONCLUSIONS: Future studies of the interactions between TLRs and herpesviridae infections, especially the subsequent signaling pathways, will not only contribute to the planning of effective antiviral therapies but also provide new molecular targets for the development of antiviral drugs.
