Hypercytokinemia is a critically fatal factor in COVID-19. However, underlying pathogenic mechanisms are unknown. Here we show that brinogen and leukotriene-A4 hydrolase (LTA4H), two of the most potent in ammatory contributors, are elevated by 67.7 and astonishing 227.7% in the plasma of patients infected by SARS-CoV-2 and admitted to intensive care unit in comparison with healthy control, respectively. Conversely, transferrin identi ed as a brinogen immobilizer in our recent work and Spink6 are down-regulated by 40.3 and 25.9%, respectively. Furthermore, we identify Spink6 as the rst endogenous inhibitor of LTA4H, a pro-in ammatory enzyme catalyzing nal and rating limited step in biosynthesis of leukotriene-B4 that is an extremely in ammatory mediator and a target to design superior anti-in ammatory drugs. Additionally, virus Spike protein is found to evoke LTA4H and brinogen expression in vivo. Collectively, these ndings identify the imbalance between in ammatory drivers and antagonists, which likely contributes to hypercytokinemia in COVID-19. Spink6 may have superior antiin ammatory function because it speci cally targets epoxide hydrolase of LTA4H to inhibit leukotriene-B4 biosynthesis without effecting LTA4H's aminopeptidase activity.

When used as a photocatalyst, titanium dioxide (TiO(2)) absorbs only ultraviolet light, and several approaches, including the use of dopants such as nitrogen, have been taken to narrow the band gap of TiO(2). We demonstrated a conceptually different approach to enhancing solar absorption by introducing disorder in the surface layers of nanophase TiO(2) through hydrogenation. We showed that disorder-engineered TiO(2) nanocrystals exhibit substantial solar-driven photocatalytic activities, including the photo-oxidation of organic molecules in water and the production of hydrogen with the use of a sacrificial reagent.

Respiratory immune characteristics associated withCoronavirus Disease 2019 (COVID-19) severity are currently unclear. We characterized bronchoalveolar lavage fluid immune cells from patients with varying severity of COVID-19 and from healthy people by using single-cell RNA sequencing. Proinflammatory monocyte-derived macrophages were abundant in the bronchoalveolar lavage fluid from patients with severe COVID-9. Moderate cases were characterized by the presence of highly clonally expanded CD8 + T cells. This atlas of the bronchoalveolar immune microenvironment suggests potential mechanisms underlying pathogenesis and recovery in COVID-19.

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Combining RNA and antibody detections significantly improved the sensitivity of pathogenic diagnosis for COVID-19 in the early phase of infection. A higher titer of Ab was independently associated with a worse clinical classification. Abstract BackgroundThe novel coronavirus SARS-CoV-2 is a newly emerging virus. The antibody response in infected patient remains largely unknown, and the clinical values of antibody testing have not been fully demonstrated. MethodsA total of 173 patients with SARS-CoV-2 infection were enrolled. Their serial plasma samples (n=535) collected during the hospitalization were tested for total antibodies (Ab), IgM and IgG against SARS-CoV-2. The dynamics of antibodies with the disease progress was analyzed. ResultsAmong 173 patients, the seroconversion rate for Ab, IgM and IgG was 93.1%, 82.7% and 64.7%, respectively. The reason for the negative antibody findings in 12 patients might due to the lack of blood samples at the later stage of illness. The median seroconversion time for Ab, IgM and then IgG were day-11, day-12 and day-14, separately. The presence of antibodies was <40% among patients within 1-week since onset, and rapidly increased to 100.0% (Ab), 94.3% (IgM) and 79.8% (IgG) since day-15 after onset. In contrast, RNA detectability decreased from 66.7% (58/87) in samples collected before day-7 to 45.5% (25/55) during day 15-39. Combining RNA and antibody detections significantly improved the sensitivity of pathogenic diagnosis for COVID-19 (p<0.001), even in early phase of 1-week since onset (p=0.007). Moreover, a higher titer of Ab was independently associated with a worse clinical classification (p=0.006). ConclusionsThe antibody detection offers vital clinical information during the course of SARS-CoV-2 infection. The findings provide strong empirical support for the routine application of serological testing in the diagnosis and management of COVID-19 patients.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents a global health emergency that is in urgent need of intervention 1-3. The entry of SARS-CoV-2 into its target cells depends on binding between the receptor-binding domain (RBD) of the viral spike protein and its cellular receptor, angiotensin-converting enzyme 2 (ACE2) 2,4-6. Here we report the isolation and characterization of 206 RBD-specific monoclonal antibodies derived from single B cells from 8 individuals infected with SARS-CoV-2. We identified antibodies that potently neutralize SARS-CoV-2; this activity correlates with competition with ACE2 for binding to RBD. Unexpectedly, the anti-SARS-CoV-2 antibodies and the infected plasma did not cross-react with the RBDs of SARS-CoV or Middle East respiratory syndrome-related coronavirus (MERS-CoV), although there was substantial plasma cross-reactivity to their trimeric spike proteins. Analysis of the crystal structure of RBD-bound antibody revealed that steric hindrance inhibits viral engagement with ACE2, thereby blocking viral entry. These findings suggest that anti-RBD antibodies are largely viral-species-specific inhibitors. The antibodies identified here may be candidates for development of clinical interventions against SARS-CoV-2. The rapid international transmission of SARS-CoV-2 poses a serious global health emergency with no available treatments or vaccine 1-3. SARS-CoV-2 shares substantial genetic and functional similarity with other human betacoronaviruses, including SARS-CoV and MERS-CoV 2,4-8. SARS-CoV-2 uses an envelope homotrimeric spike glycoprotein to interact with the cellular receptor ACE2 2,5,6,8. Binding with ACE2 triggers a cell membrane fusion cascade that results in viral entry. This suggests that disruption of the RBD-ACE2 interaction would block SARS-CoV-2 cell entry. The high-resolution structure of SARS-CoV-2 RBD bound to the N-terminal peptidase domain of ACE2 has recently been determined 6-8. The ACE2-binding mechanism is nearly identical between SARS-CoV-2 and SARS-CoV RBDs 7-10. Animal studies on RBD-based vaccines against SARS-CoV and MERS-CoV have shown strong polyclonal antibody responses that inhibit viral entry 11,12. These findings suggest that anti-RBD antibodies should effectively block SARS-CoV-2 entry. In this study, we report on RBD-specific monoclonal antibodies obtained from individuals infected with SARS-CoV-2. Plasma antibody response against SARS-CoV-2 We collected cross-sectional and longitudinal blood samples from eight patients infected with SARS-CoV-2, who were infected during the early outbreak in Shenzhen (Supplementary Table 1). Samples were named according to patient ID and A, B, or C depending on when they were collected. Six patients (P1 to P4, P8 and P16) had recently travelled to Wuhan and the others (P5 and P22) had direct contact with people who had recently been in Wuhan. P1 to P5 comprise a family cluster, including the first documented case of human-to-human transmission...

Programmed necrotic cell death induced by the tumor necrosis factor alpha (TNF-α) family of cytokines is dependent on a kinase cascade consisting of receptor-interacting kinases RIP1 and RIP3. How these kinase activities cause cells to die by necrosis is not known. The mixed lineage kinase domain-like protein MLKL is a functional RIP3 substrate that binds to RIP3 through its kinase-like domain but lacks kinase activity of its own. RIP3 phosphorylates MLKL at the T357 and S358 sites. Reported here is the development of a monoclonal antibody that specifically recognizes phosphorylated MLKL in cells dying of this pathway and in human liver biopsy samples from patients suffering from drug-induced liver injury. The phosphorylated MLKL forms an oligomer that binds to phosphatidylinositol lipids and cardiolipin. This property allows MLKL to move from the cytosol to the plasma and intracellular membranes, where it directly disrupts membrane integrity, resulting in necrotic death.