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1.
Nat Commun ; 12(1): 5000, 2021 08 17.
Article in English | MEDLINE | ID: covidwho-1361637

ABSTRACT

The successive emergences and accelerating spread of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineages and evolved resistance to some ongoing clinical therapeutics increase the risks associated with the coronavirus disease 2019 (COVID-19) pandemic. An urgent intervention for broadly effective therapies to limit the morbidity and mortality of COVID-19 and future transmission events from SARS-related coronaviruses (SARSr-CoVs) is needed. Here, we isolate and humanize an angiotensin-converting enzyme-2 (ACE2)-blocking monoclonal antibody (MAb), named h11B11, which exhibits potent inhibitory activity against SARS-CoV and circulating global SARS-CoV-2 lineages. When administered therapeutically or prophylactically in the hACE2 mouse model, h11B11 alleviates and prevents SARS-CoV-2 replication and virus-induced pathological syndromes. No significant changes in blood pressure and hematology chemistry toxicology were observed after injections of multiple high dosages of h11B11 in cynomolgus monkeys. Analysis of the structures of the h11B11/ACE2 and receptor-binding domain (RBD)/ACE2 complexes shows hindrance and epitope competition of the MAb and RBD for the receptor. Together, these results suggest h11B11 as a potential therapeutic countermeasure against SARS-CoV, SARS-CoV-2, and escape variants.


Subject(s)
Angiotensin-Converting Enzyme 2/drug effects , Angiotensin-Converting Enzyme 2/immunology , Antibodies, Neutralizing/administration & dosage , COVID-19/drug therapy , SARS-CoV-2/drug effects , Animals , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , COVID-19/immunology , COVID-19/mortality , COVID-19/virology , Chlorocebus aethiops , Disease Models, Animal , Epitopes , Female , HEK293 Cells , Haplorhini , Humans , Macaca fascicularis , Male , Mice , Mice, Inbred BALB C , Pandemics , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Vero Cells , Virus Activation
2.
Front Immunol ; 12: 661052, 2021.
Article in English | MEDLINE | ID: covidwho-1229177

ABSTRACT

While lymphocytopenia is a common characteristic of coronavirus disease 2019 (COVID-19), the mechanisms responsible for this lymphocyte depletion are unclear. Here, we retrospectively reviewed the clinical and immunological data from 18 fatal COVID-19 cases, results showed that these patients had severe lymphocytopenia, together with high serum levels of inflammatory cytokines (IL-6, IL-8 and IL-10), and elevation of many other mediators in routine laboratory tests, including C-reactive protein, lactate dehydrogenase, α-hydroxybutyrate dehydrogenase and natriuretic peptide type B. The spleens and hilar lymph nodes (LNs) from six additional COVID-19 patients with post-mortem examinations were also collected, histopathologic detection showed that both organs manifested severe tissue damage and lymphocyte apoptosis in these six cases. In situ hybridization assays illustrated that SARS-CoV-2 viral RNA accumulates in these tissues, and transmission electronic microscopy confirmed that coronavirus-like particles were visible in the LNs. SARS-CoV-2 Spike and Nucleocapsid protein (NP) accumulated in the spleens and LNs, and the NP antigen restricted in angiotensin-converting enzyme 2 (ACE2) positive macrophages and dendritic cells (DCs). Furthermore, SARS-CoV-2 triggered the transcription of Il6, Il8 and Il1b genes in infected primary macrophages and DCs in vitro, and SARS-CoV-2-NP+ macrophages and DCs also manifested high levels of IL-6 and IL-1ß, which might directly decimate human spleens and LNs and subsequently lead to lymphocytopenia in vivo. Collectively, these results demonstrated that SARS-CoV-2 induced lymphocytopenia by promoting systemic inflammation and direct neutralization in human spleen and LNs.


Subject(s)
COVID-19/immunology , Lymph Nodes/immunology , Lymphopenia/immunology , SARS-CoV-2/immunology , Spleen/immunology , Angiotensin-Converting Enzyme 2/immunology , COVID-19/complications , COVID-19/pathology , Coronavirus Nucleocapsid Proteins/immunology , Cytokines/immunology , Female , Humans , Inflammation/immunology , Inflammation/pathology , Lymph Nodes/ultrastructure , Lymphopenia/etiology , Lymphopenia/pathology , Middle Aged , Phosphoproteins/immunology , RNA, Messenger/immunology , Retrospective Studies , SARS-CoV-2/pathogenicity , SARS-CoV-2/ultrastructure , Spleen/ultrastructure
3.
Nat Commun ; 12(1): 2506, 2021 05 04.
Article in English | MEDLINE | ID: covidwho-1216457

ABSTRACT

It is unclear whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can directly infect human kidney, thus leading to acute kidney injury (AKI). Here, we perform a retrospective analysis of clinical parameters from 85 patients with laboratory-confirmed coronavirus disease 2019 (COVID-19); moreover, kidney histopathology from six additional COVID-19 patients with post-mortem examinations was performed. We find that 27% (23/85) of patients exhibited AKI. The elderly patients and cases with comorbidities (hypertension and heart failure) are more prone to develop AKI. Haematoxylin & eosin staining shows that the kidneys from COVID-19 autopsies have moderate to severe tubular damage. In situ hybridization assays illustrate that viral RNA accumulates in tubules. Immunohistochemistry shows nucleocapsid and spike protein deposits in the tubules, and immunofluorescence double staining shows that both antigens are restricted to the angiotensin converting enzyme-II-positive tubules. SARS-CoV-2 infection triggers the expression of hypoxic damage-associated molecules, including DP2 and prostaglandin D synthase in infected tubules. Moreover, it enhances CD68+ macrophages infiltration into the tubulointerstitium, and complement C5b-9 deposition on tubules is also observed. These results suggest that SARS-CoV-2 directly infects human kidney to mediate tubular pathogenesis and AKI.


Subject(s)
Acute Kidney Injury/etiology , COVID-19/complications , Kidney Tubules/virology , SARS-CoV-2/pathogenicity , Acute Kidney Injury/epidemiology , Acute Kidney Injury/pathology , Acute Kidney Injury/virology , Adult , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/metabolism , Antigens, Viral/genetics , Antigens, Viral/metabolism , COVID-19/epidemiology , COVID-19/virology , China/epidemiology , Female , Humans , Immunity, Innate , Kidney Function Tests , Kidney Tubules/metabolism , Kidney Tubules/pathology , Male , Middle Aged , Pandemics , Retrospective Studies , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Viral Proteins/genetics , Viral Proteins/metabolism , Young Adult
4.
Clin Infect Dis ; 71(16): 2150-2157, 2020 11 19.
Article in English | MEDLINE | ID: covidwho-1153175

ABSTRACT

BACKGROUND: Thymosin alpha 1 (Tα1) had been used in the treatment of viral infections as an immune response modifier for many years. However, clinical benefits and the mechanism of Tα1 treatment for COVID-19 patients are still unclear. METHODS: We retrospectively reviewed the clinical outcomes of 76 severe COVID-19 cases admitted to 2 hospitals in Wuhan, China, from December 2019 to March 2020. The thymus output in peripheral blood mononuclear cells from COVID-19 patients was measured by T-cell receptor excision circles (TRECs). The levels of T-cell exhaustion markers programmed death-1 (PD-1) and T-cell immunoglobulin and mucin domain protein 3 (Tim-3) on CD8+ T cells were detected by flow cytometry. RESULTS: Compared with the untreated group, Tα1 treatment significantly reduced the mortality of severe COVID-19 patients (11.11% vs 30.00%, P = .044). Tα1 enhanced blood T-cell numbers in COVID-19 patients with severe lymphocytopenia. Under such conditions, Tα1 also successfully restored CD8+ and CD4+ T-cell numbers in elderly patients. Meanwhile, Tα1 reduced PD-1 and Tim-3 expression on CD8+ T cells from severe COVID-19 patients compared with untreated cases. It is of note that restoration of lymphocytopenia and acute exhaustion of T cells were roughly parallel to the rise of TRECs. CONCLUSIONS: Tα1 treatment significantly reduced mortality of severe COVID-19 patients. COVID-19 patients with counts of CD8+ T cells or CD4+ T cells in circulation less than 400/µL or 650/µL, respectively, gained more benefits from Tα1. Tα1 reversed T-cell exhaustion and recovered immune reconstitution through promoting thymus output during severe acute respiratory syndrome-coronavirus 2 infection.


Subject(s)
COVID-19/mortality , Lymphopenia/metabolism , SARS-CoV-2/pathogenicity , Thymalfasin/metabolism , Adult , Aged , CD4-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/metabolism , COVID-19/virology , Female , Humans , Male , Middle Aged , Retrospective Studies , Thymalfasin/genetics , Thymus Gland/metabolism
5.
Front Immunol ; 11: 827, 2020.
Article in English | MEDLINE | ID: covidwho-332452

ABSTRACT

Background: The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has posed great threat to human health. T cells play a critical role in antiviral immunity but their numbers and functional state in COVID-19 patients remain largely unclear. Methods: We retrospectively reviewed the counts of T cells and serum cytokine concentration from data of 522 patients with laboratory-confirmed COVID-19 and 40 healthy controls. In addition, the expression of T cell exhaustion markers were measured in 14 COVID-19 cases. Results: The number of total T cells, CD4+ and CD8+ T cells were dramatically reduced in COVID-19 patients, especially in patients requiring Intensive Care Unit (ICU) care. Counts of total T cells, CD8+ T cells or CD4+ T cells lower than 800, 300, or 400/µL, respectively, were negatively correlated with patient survival. T cell numbers were negatively correlated to serum IL-6, IL-10, and TNF-α concentration, with patients in the disease resolution period showing reduced IL-6, IL-10, and TNF-α concentrations and restored T cell counts. T cells from COVID-19 patients had significantly higher levels of the exhausted marker PD-1. Increasing PD-1 and Tim-3 expression on T cells was seen as patients progressed from prodromal to overtly symptomatic stages. Conclusions: T cell counts are reduced significantly in COVID-19 patients, and the surviving T cells appear functionally exhausted. Non-ICU patients with total T cells counts lower than 800/µL may still require urgent intervention, even in the immediate absence of more severe symptoms due to a high risk for further deterioration in condition.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , COVID-19 , Coronavirus Infections/blood , Coronavirus Infections/pathology , Cytokines/blood , Humans , Lymphocyte Count , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/pathology , SARS-CoV-2 , T-Lymphocytes/immunology
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