No abstract

Development of antibody protection during SARS-CoV-2 infection is a pressing question for public health and for vaccine development. We developed highly sensitive SARS-CoV-2-specific antibody and neutralization assays. SARS-CoV-2 Spike protein or Nucleocapsid protein specific IgG antibodies at titers more than 1:100,000 were detectable in all PCR+ subjects (n = 115) and were absent in the negative controls. Other isotype antibodies (IgA, IgG1-4) were also detected. SARS-CoV-2 neutralization was determined in COVID-19 and convalescent plasma at up to 10,000-fold dilution, using Spike protein pseudotyped lentiviruses, which were also blocked by neutralizing antibodies (NAbs). Hospitalized patients had up to 3000-fold higher antibody and neutralization titers compared to outpatients or convalescent plasma donors. Interestingly, some COVID-19 patients also possessed NAbs against SARS-CoV Spike protein pseudovirus. Together these results demonstrate the high specificity and sensitivity of our assays, which may impact understanding the quality or duration of the antibody response during COVID-19 and in determining the effectiveness of potential vaccines.

Background: COVID-19 can present with lymphopenia and extraordinary complex multiorgan pathologies that can trigger long-term sequela.Aims: Given that inflammasome products, like caspase-1, play a role in the pathophysiology of a number of co-morbid conditions, we investigated caspases across the spectrum of COVID-19 disease. Materials & Methods:We assessed transcriptional states of multiple caspases and using flow cytometry, the expression of active caspase-1 in blood cells from COVID-19 patients in acute and convalescent stages of disease. Non-COVID-19 subject presenting with various comorbid conditions served as controls.Results: Single-cell RNA-seq data of immune cells from COVID-19 patients showed a distinct caspase expression pattern in T cells, neutrophils, dendritic cells, and eosinophils compared with controls. Caspase-1 was upregulated in CD4+ T-cells from hospitalized COVID-19 patients compared with unexposed controls. Post-COVID-19 patients with lingering symptoms (long-haulers) also showed upregulated caspase-1activity in CD4+ T-cells that ex vivo was attenuated with a select pan-caspase inhibitor. We observed elevated caspase-3/7levels in red blood cells from COVID-19 patients compared with controls that was reduced following caspase inhibition. Discussion: Our preliminary results suggest an exuberant caspase response in COVID-19 that may facilitate immune-related pathological processes leading to severe outcomes. Further clinical correlations of caspase expression in different stages of COVID-19 will be needed. Conclusion:Pan-caspase inhibition could emerge as a therapeutic strategy to ameliorate or prevent severe COVID-19.

supplementary data for Table S1, reviewed data of all previous cases. CMB made a critical revision of the manuscript, helped in the acquisition of data, provided supplementary data for Table S1, reviewed data of all previous cases. All authors revised and gave the approval of the final manuscript.

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a significant global health emergency with new variants in some cases evading current therapies and approved vaccines. COVID-19 presents with a broad spectrum of acute and long-term manifestations. Severe COVID-19 is characterized by dysregulated cytokine release profile, dysfunctional immune responses, and hypercoagulation with a high risk of progression to multi-organ failure and death. Unraveling the fundamental immunological processes underlying the clinical manifestations of COVID-19 is vital for the identification and design of more effective therapeutic interventions for individuals at the highest risk of severe outcomes. Caspases are expressed in both immune and non-immune cells and mediate inflammation and cell death, including apoptosis and pyroptosis. Here we review accumulating evidence defining the importance of the expression and activity of caspase family members following SARS-CoV-2 infection and disease. Research suggests SARS-CoV-2 infection is linked to the function of multiple caspases, both mechanistically in vitro as well as in observational studies of individuals with severe COVID-19, which may further the impact on disease severity. We also highlight immunological mechanisms that occur in severe COVID-19 pathology upstream and downstream of activated caspase pathways, including innate recognition receptor signaling, inflammasomes, and other multiprotein complex assembly, inflammatory mediators IL-1β and IL-18, and apoptotic and pyroptotic cell death. Finally, we illuminate discriminate and indiscriminate caspase inhibitors that have been identified for clinical use that could emerge as potential therapeutic interventions that may benefit clinical efforts to prevent or ameliorate severe COVID-19.

At present, there are is no effective vaccine and only one FDA approved early-stage therapy against infection with the SARS-CoV-2 virus to prevent disease progression. The excessive inflammation and tissue damage associated with COVID-19 can lead to immediate (i.e. respiratory failure, sepsis, and ultimately, death) or long-term health problems (i.e. fatigue, dyspnea, cough, joint pain, anosmia) and the risk for these complications are higher in the elderly population, certain ethnic groups, as well as those with various co-morbid conditions. Cellular caspases play a role in the pathophysiology of a number of disorders that overlap with the list of co-morbid conditions seen in severe COVID-19. In this study, we assessed transcriptional states of caspases in immune cells from COVID-19 patients and profiled intra-cellular caspases in immune cells and red blood cells derived from a spectrum of COVID-19 patients hospitalized with acute disease or convalescent. Gene expression levels of select caspases were increased in in vitro SARS-CoV-2 infection models and single cell RNA-Seq data of peripheral blood from COVID-19 patients showed a distinct pattern of caspase expression in T cell, neutrophils, and dendritic cells. Flow cytometric evaluation of CD4 T cells showed up-regulation of caspase-1 in hospitalized COVID-19 patients compared to unexposed controls, with the exception of a subset of patients with asthma and chronic rhinosinusitis (CRS). Convalescent COVID-19 patients with lingering symptoms (long haulers) showed persistent up-regulation of caspase-1 in CD4 T cells that was attenuated ex vivo following co-culture with a select pan-caspase inhibitor. Further, we observed elevated caspase 3 levels in red blood cells from COVID-19 patients compared to controls that were responsive to caspase inhibition. Taken together, our results expose an exuberant caspase response in COVID-19 that may facilitate immune-related pathological processes leading to severe outcomes. Pan-caspase inhibition could emerge as a therapeutic strategy to ameliorate, reduce, or prevent severe COVID-19 outcomes.

No abstract

COVID-19 can present with lymphopenia and extraordinary complex multi-organ pathologies that can trigger long-term sequela. Given that inflammasome products, like caspase-1, play a role in the pathophysiology of a number of co-morbid conditions, we investigated caspases across the spectrum of COVID-19 disease. We assessed transcriptional states of multiple caspases and using flow cytometry, the expression of active caspase-1 in blood cells from COVID-19 patients in acute and convalescent stages of disease. Non-COVID-19 subjects presenting with various co-morbid conditions served as controls. Single-cell RNA-seq data of immune cells from COVID-19 patients showed a distinct caspase expression pattern in T cells, neutrophils, dendritic cells and eosinophils compared to controls. Caspase-1 was upregulated in CD4+ T-cells from hospitalized COVID-19 patients compared to unexposed controls. Post-COVID-19 patients with lingering symptoms (long-haulers) also showed up-regulated caspase-1 activity in CD4+ T-cells that ex vivo was attenuated with a select pan-caspase inhibitor. We observed elevated caspase-3/7 levels in red blood cells from COVID-19 patients compared to controls that was reduced following caspase inhibition. Our preliminary results suggest an exuberant caspase response in COVID-19 that may facilitate immune-related pathological processes leading to severe outcomes. Further clinical correlations of caspase expression in different stages of COVID-19 will be needed. Pan-caspase inhibition could emerge as a therapeutic strategy to ameliorate or prevent severe COVID-19.