ABSTRACT
The ongoing SARS-CoV-2 pandemic represents a brutal reminder of the continual threat of mucosal infectious diseases. Mucosal immunity may provide robust protection at the predominant sites of SARS-CoV-2 infection. However, it remains unclear whether respiratory mucosal administration of DNA vaccines could confer protective immune responses against SARS-CoV-2 challenge due to the insurmountable barriers posed by the airway. Here, we applied self-assembled peptide-poloxamine nanoparticles with mucus-penetrating properties for pulmonary inoculation of a COVID-19 DNA vaccine (pSpike/PP-sNp). Not only displays the pSpike/PP-sNp superior gene-transfection and favorable biocompatibility in the mouse airway, but pSpike/PP-sNp promotes a tripartite immunity consisting of systemic, cellular and mucosal immune responses that are characterized by mucosal IgA secretion, high levels of neutralizing antibodies, and resident memory phenotype T-cell responses in the lungs of mice. Most importantly, pSpike/PP-sNp completely eliminates SARS-CoV-2 infection in both upper and lower respiratory tracts and enables 100% survival rate of mice following lethal SARS-CoV-2 challenge. Our findings indicate PP-sNp might be a promising platform in mediating DNA vaccines to elicit all-around mucosal immunity against SARS-CoV-2.
Subject(s)
COVID-19 , Communicable DiseasesABSTRACT
Currently, it is not clear whether antibody-mediated enhancement (ADE) is involved in the pathogenesis of COVID-19, and the occurrence condition for ADE needs to be elucidated. We demonstrated that different from the reported RBD-targeting neutralizing antibody XG005 which elicits an ACE2-independent ADE on Raji cells, neutralizing antibody CB6, mouse anti-S1 serum and convalescent plasma could not elicit ADE on Raji cells; instead, they could elicit ADE on cells with FcγRIIA/CD32A expression and small amount of endogenous ACE2. ADE occurred at sub-neutralizing antibody concentrations, and the maximum induction concentration of ADE was correlated with IC50, implying that part of unneutralized S protein is essential for ADE. The enhanced infectivity of 614G variant was higher than that of 614D wildtype in the presence of antibodies, further indicating that ADE may be influenced by the virus strains with different ACE2 binding affinity and infectivity. ADE was proved to be FcγRII-dependent, and knockdown of ACE2 or the application of fusion-inhibition peptide EK1C4 significantly impaired ADE. In conclusion, our results identified a novel ADE mechanism for neutralizing antibodies against SARS-CoV-2. In certain circumstance, ACE2 may act as the secondary receptor in the antibody and FcγR-mediated enhanced entry of SARS-CoV-2.Funding: This work is supported by National Key R&D Program of China (2020YFA0707600), Natural Science Foundation of China (82170015), Medical and Health Science Technology Innovation Project of Chinese Academy of Medical Sciences (2020-I2M-2-014), Project of BRC-BC (Biomedical Translational Engineering Research Center of BUCT-CJFH) (XK2020-09), Natural Science Foundation of China (82041011/H0104 & 81800002/H0101); Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Sciences (CIFMS 2018-I2M-1-003 & 2020-I2M-CoV19-005).Declaration of Interests: The authors declare no competing interests.Ethics Approval Statement: The plasma from convalescent patients were collected 6 months after their discharge, with informed consent signed by every patient. The procedures were approved by the Ethics Committee in China- Japan Friendship Hospital (Beijing, China), and complied with all relevant ethical regulations regarding human research.
Subject(s)
COVID-19ABSTRACT
Background: The pandemic of Coronavirus disease 2019 (COVID-19) is ongoing globally, which is a big challenge for public health. Alteration of human microbiota had been observed in COVID-19. However, it is unknown how the microbiota is associated with the fatality in COVID-19.Methods: We conducted metatranscriptome sequencing on 588 longitudinal oropharyngeal swab specimens collected from 192 COVID-19 patients recruited in the LOTUS clinical trial (Registration number: ChiCTR2000029308) (including 39 deceased patients), and 95 healthy controls from the same geographic area.Findings: The upper respiratory tract (URT) microbiota in COVID-19 patients differed from that in healthy controls, while deceased patients possessed a more distinct microbiota. Streptococcus was enriched in recovered patients, whereas potential pathogens, including Candida and Enterococcus, were more abundant in deceased patients. Moreover, the microbiota dominated by Streptococcus was more stable than that dominated by other species. In contrast, the URT microbiota in deceased patients showed a more significant alteration and became more deviated from the norm after admission. The abundance of Streptococcus on admission, particularly that of S. parasanguis, was identified as a strong predictor of fatality by Cox and L1 regularized logistic regression analysis, thus could be used as a potential prognostic biomarker of COVID-19.Interpretation Alteration of the URT microbiota was observed in COVID-19 patients and was associated with the fatality rate. A higher abundance of Streptococcus, especially S. parasanguis, on admission in oropharyngeal swabs predicts a better outcome. The generalization of the results in other populations and underlying mechanisms need further investigations.Trial Registration: Participants were enrolled in ChiCTR2000029308.Funding: This study was funded in part by the National Major Science & Technology Project for Control and Prevention of Major Infectious Diseases in China (2017ZX10103004, 2018ZX10301401), the Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Sciences (2019-I2M-2-XX, 2016-I2M-1-014, 2018-I2M-1-003), The Non-profit Central Research Institute Fund of CAMS (2020HY320001, 2019PT310029), Beijing Advanced Innovation Center for Genomics (ICG), and Beijing Advanced Innovation Center for Structural Biology (ICSB).Declaration of Interests: All authors declare no competing interests.Ethics Approval Statement: The study was approved by the Institutional Review Board of Jin Yin-Tan Hospital (KY2020-02.01). Written informed consent was obtained from all patients or their legal representatives if they were too unwell to provide consent.
Subject(s)
COVID-19 , Respiratory Tract InfectionsABSTRACT
The pandemic of Coronavirus disease 2019 (COVID-19) is ongoing globally, which is a big challenge for public health. Alteration of human microbiota had been observed in COVID-19. However, it is unknown how the microbiota is associated with the fatality in COVID-19. We conducted metatranscriptome sequencing on 588 longitudinal oropharyngeal swab specimens collected from 192 COVID-19 patients recruited in the LOTUS clinical trial (Registration number: ChiCTR2000029308) (including 39 deceased patients), and 95 healthy controls from the same geographic area. The upper respiratory tract (URT) microbiota in COVID-19 patients differed from that in healthy controls, while deceased patients possessed a more distinct microbiota. Streptococcus was enriched in recovered patients, whereas potential pathogens, including Candida and Enterococcus, were more abundant in deceased patients. Moreover, the microbiota dominated by Streptococcus was more stable than that dominated by other species. In contrast, the URT microbiota in deceased patients showed a more significant alteration and became more deviated from the norm after admission. The abundance of Streptococcus on admission, particularly that of S. parasanguinis, was identified as a strong predictor of fatality by Cox and L1 regularized logistic regression analysis, thus could be used as a potential prognostic biomarker of COVID-19. The generalization of the results in other populations and underlying mechanisms needs further investigations.
Subject(s)
COVID-19ABSTRACT
Background: Seasonal human coronaviruses (HCoVs) including HCoV-229E, -OC43, -NL63 and -HKU1 are widely spreading in global human populations. However, the relevance of humoral response against seasonal HCoVs to COVID-19 pathogenesis is elusive.Methods: We profiled the temporal changes of IgG antibodies against spike (S; S-IgG) proteins of SARS-CoV-2 and seasonal HCoVs in 838 plasma samples collected from 344 COVID-19 patients. We tested the antigenic cross-reactivity of S protein between SARS-CoV-2 and seasonal HCoVs and evaluated the correlations between HCoV-OC43 S-IgG antibody and disease severity in COVID-19 patients.Findings: SARS-CoV-2 S-IgG titers mounted until days 22–28, whereas HCoV-OC43 antibody titers increased until days 15–21 and then plateaued until day 46. However, IgG antibody titers against HCoV-NL63, -229E, and -HKU1 showed no significant increasing. A two-way cross-reactivity was identified between SARS-CoV-2 and HCoV-OC43. Neutralizing antibodies against SARS-CoV-2 were not detected in healthy controls who were positive for HCoV-OC43 S-IgG. HCoV-OC43 S-IgG titers were significantly higher in patients with severe disease than those in mild/moderate patients at days 1–21 post symptom onset (PSO). Higher levels of HCoV-OC43 S-IgG were also observed in patients requiring mechanical ventilation and the elderly. At days 1–10 PSO, HCoV-OC43 S-IgG titers correlated to disease severity in all age groups, and to fatality in over 60-year group.Interpretation: Our data indicate that there exist a humoral cross-reactive response between HCoV-OC43 and SARS-CoV-2. The cross-reactive HCoV-OC43 S-IgG antibody is not protective against SARS-CoV-2, but may be a risk factor for the severity and adverse outcome of COVID-19.Funding Statement: This study was funded in part by the National Major Science & Technology Project for Control and Prevention of Major Infectious Diseases in China (2017ZX10204401, 2018ZX10734404), Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Sciences (2016-I2M-1–014, 2018-I2M-1-003, 2020-I2M-1-001, 2020-I2M-CoV19-005), Natural Science Foundation of China (82041011/H0104), and National Key R&D Program of China (2020YFA0707600). Declaration of Interests: The authors declare no competing interests.Ethics Approval Statement: This study was approved by the Ethical Review Board of Wuhan Jinyintan Hospital, Infectious Disease Hospital of Heilongjiang Province (Harbin), and Institute of Pathogen Biology, Chinese Academy of Medical Sciences. Written informed consent was obtained from each healthy volunteer and COVID-19 patients in cohort 4. Written informed consents from the remaining patients were waived in light of the emerging infectious disease of high public health relevance.
Subject(s)
Vision Disorders , COVID-19 , Communicable DiseasesABSTRACT
Background: Upper respiratory tract specimens are widely applicable for the diagnosis of COVID-19. To date, no study has analyzed the actual viral loads in upper respiratory tract and its relationship with the severity of lung lesions, Ct value of RT-PCR and transmission capacity in COVID-19 patients.Methods: We retrospectively enrolled nine COVID-19 patients. Clinical data and close contacts of these patients were investigated. Respiratory samples were tested for SARS-CoV-2 with both normal RT-PCR and droplet digital PCR.Results: All the COVID-19 patients complicated with pneumonia. Viral loads in nasopharyngeal swabs were accurately quantified, and they had no direct correspondence with the severity of lung lesions. The Cycle Threshold (Ct) value of RT-PCR was approximately consistent with the absolute quantification of digital PCR. The spearman correlation coefficient between them was -0.952 with P value < 0.001. Close contacts of patients with very low viral load or no detected virus were not infected.Conclusions: Viral loads in nasopharyngeal swabs, could not predict the severity of lung lesions revealed by CT in COVID-19 patients. The infectious capacity of patients with low or absent viral load in upper respiratory tract was relatively weak, and wearing mask might be helpful for lower its spread.
Subject(s)
COVID-19 , Pneumonia , Lung DiseasesABSTRACT
2019 Novel Coronavirus (2019-nCoV) is a virus identified as the cause of the outbreak of pneumonia first detected in Wuhan, China. Investigations on the transmissibility, severity, and other features associated with this virus are ongoing. Currently, there is no vaccine or therapeutic antibody to prevent the infection, and more time is required to develop an effective immune strategy against the pathogen. In contrast, specific inhibitors targeting the key protease involved in replication and proliferation of the virus are the most effective means to alleviate the epidemic. The main protease of SARS-CoV is essential for the life cycle of the virus, which showed 96.1% of similarity with the main proteaseof 2019-nCoV, is considered to be an attractive target for drug development. In this study, we have identified 4 small molecular drugs with high binding capacity with SARS-CoV main protease by high-throughput screening based on the 8,000 clinical drug libraries, all these drugs have been widely used in clinical applications with guaranteed safety, which may serve as promising candidates to treat the infection of 2019-nCoV.