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1.
Cell Discov ; 7(1): 60, 2021 Aug 04.
Article in English | MEDLINE | ID: covidwho-1541177

ABSTRACT

Severe coronavirus disease 2019 (COVID-19) is often indicated by lymphopenia and increased myelopoiesis; however, the underlying mechanism is still unclear, especially the alteration of hematopoiesis. It is important to explore to what extent and how hematopoietic stem cells contribute to the impairment of peripheral lymphoid and myeloid compartments in COVID-19 patients. In this study, we used single-cell RNA sequencing to assess bone marrow mononuclear cells from COVID-19 patients with peripheral blood mononuclear cells as control. The results showed that the hematopoietic stem cells in these patients were mainly in the G1 phase and prone to apoptosis, with immune activation and anti-viral responses. Importantly, a significant accumulation of immature myeloid progenitors and a dramatic reduction of lymphoid progenitors in severe cases were identified, along with the up-regulation of transcription factors (such as SPI1, LMO4, ETS2, FLI1, and GATA2) that are important for the hematopoietic stem cell or multipotent progenitor to differentiate into downstream progenitors. Our results indicate a dysregulated hematopoiesis in patients with severe COVID-19.

2.
ACS Nano ; 15(10): 15754-15770, 2021 10 26.
Article in English | MEDLINE | ID: covidwho-1454714

ABSTRACT

Multiple successful vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are urgently needed to address the ongoing coronavirus disease 2019 (Covid-19) pandemic. In the present work, we describe a subunit vaccine based on the SARS-CoV-2 spike protein coadministered with CpG adjuvant. To enhance the immunogenicity of our formulation, both antigen and adjuvant were encapsulated with our proprietary artificial cell membrane (ACM) polymersome technology. Structurally, ACM polymersomes are self-assembling nanoscale vesicles made up of an amphiphilic block copolymer comprising poly(butadiene)-b-poly(ethylene glycol) and a cationic lipid, 1,2-dioleoyl-3-trimethylammonium-propane. Functionally, ACM polymersomes serve as delivery vehicles that are efficiently taken up by dendritic cells (DC1 and DC2), which are key initiators of the adaptive immune response. Two doses of our formulation elicit robust neutralizing antibody titers in C57BL/6 mice that persist at least 40 days. Furthermore, we confirm the presence of functional memory CD4+ and CD8+ T cells that produce T helper type 1 cytokines. This study is an important step toward the development of an efficacious vaccine in humans.


Subject(s)
COVID-19 Vaccines/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Neutralizing , Antibodies, Viral , CD8-Positive T-Lymphocytes , COVID-19/prevention & control , Humans , Mice , Mice, Inbred C57BL , Nanoparticles , Protein Subunits , SARS-CoV-2 , Vaccines, Subunit
3.
Cell Death Differ ; 28(12): 3297-3315, 2021 12.
Article in English | MEDLINE | ID: covidwho-1298835

ABSTRACT

Patients with cancer are at higher risk of severe coronavirus infectious disease 2019 (COVID-19), but the mechanisms underlying virus-host interactions during cancer therapies remain elusive. When comparing nasopharyngeal swabs from cancer and noncancer patients for RT-qPCR cycle thresholds measuring acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in 1063 patients (58% with cancer), we found that malignant disease favors the magnitude and duration of viral RNA shedding concomitant with prolonged serum elevations of type 1 IFN that anticorrelated with anti-RBD IgG antibodies. Cancer patients with a prolonged SARS-CoV-2 RNA detection exhibited the typical immunopathology of severe COVID-19 at the early phase of infection including circulation of immature neutrophils, depletion of nonconventional monocytes, and a general lymphopenia that, however, was accompanied by a rise in plasmablasts, activated follicular T-helper cells, and non-naive Granzyme B+FasL+, EomeshighTCF-1high, PD-1+CD8+ Tc1 cells. Virus-induced lymphopenia worsened cancer-associated lymphocyte loss, and low lymphocyte counts correlated with chronic SARS-CoV-2 RNA shedding, COVID-19 severity, and a higher risk of cancer-related death in the first and second surge of the pandemic. Lymphocyte loss correlated with significant changes in metabolites from the polyamine and biliary salt pathways as well as increased blood DNA from Enterobacteriaceae and Micrococcaceae gut family members in long-term viral carriers. We surmise that cancer therapies may exacerbate the paradoxical association between lymphopenia and COVID-19-related immunopathology, and that the prevention of COVID-19-induced lymphocyte loss may reduce cancer-associated death.


Subject(s)
COVID-19/complications , COVID-19/virology , Lymphopenia/complications , Neoplasms/complications , RNA, Viral/analysis , SARS-CoV-2/genetics , Virus Shedding , Adolescent , Adult , Aged , Aged, 80 and over , Cohort Studies , DNA, Bacterial/blood , Enterobacteriaceae/genetics , Female , Humans , Interferon Type I/blood , Lymphopenia/virology , Male , Micrococcaceae/genetics , Middle Aged , Nasopharynx/virology , Neoplasms/diagnosis , Neoplasms/mortality , Pandemics , Prognosis , Time Factors , Young Adult
4.
Front Immunol ; 12: 674279, 2021.
Article in English | MEDLINE | ID: covidwho-1266662

ABSTRACT

An accurate depiction of the convalescent COVID-19 immunome will help delineate the immunological milieu crucial for disease resolution and protection. Using mass cytometry, we characterized the immune architecture in patients recovering from mild COVID-19. We identified a virus-specific immune rheostat composed of an effector T (Teff) cell recall response that is balanced by the enrichment of a highly specialized regulatory T (Treg) cell subset. Both components were reactive against a peptide pool covering the receptor binding domain (RBD) of the SARS-CoV-2 spike glycoprotein. We also observed expansion of IFNγ+ memory CD4+ T cells and virus-specific follicular helper T (TFH) cells. Overall, these findings pinpoint critical immune effector and regulatory mechanisms essential for a potent, yet harmless resolution of COVID-19 infection.


Subject(s)
COVID-19/immunology , SARS-CoV-2/immunology , Adolescent , Adult , CD4-Positive T-Lymphocytes/immunology , Child , Child, Preschool , Female , Humans , Male , Spike Glycoprotein, Coronavirus/immunology , T Follicular Helper Cells/immunology , T-Lymphocytes, Regulatory/immunology , Young Adult
5.
Immunol Cell Biol ; 99(6): 561-564, 2021 07.
Article in English | MEDLINE | ID: covidwho-1247185
6.
Front Med (Lausanne) ; 8: 603374, 2021.
Article in English | MEDLINE | ID: covidwho-1221950

ABSTRACT

The recent coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2. COVID-19 was first reported in China (December 2019) and is now prevalent across the globe. Entry of severe acute respiratory syndrome coronavirus 2 into mammalian cells requires the binding of viral Spike (S) proteins to the angiotensin-converting enzyme 2 receptor. Once entered, the S protein is primed by a specialized serine protease, transmembrane serine protease 2 in the host cell. Importantly, besides the respiratory symptoms that are consistent with other common respiratory virus infections when patients become viremic, a significant number of COVID-19 patients also develop liver comorbidities. We explored whether a specific target cell-type in the mammalian liver could be implicated in disease pathophysiology other than the general deleterious response to cytokine storms. Here, we used single-cell RNA-seq to survey the human liver and identified potentially implicated liver cell-type for viral ingress. We analyzed ~300,000 single cells across five different (i.e., human fetal, healthy, cirrhotic, tumor, and adjacent normal) liver tissue types. This study reports on the co-expression of angiotensin-converting enzyme 2 and transmembrane serine protease 2 in a TROP2+ liver progenitor population. Importantly, we detected enrichment of this cell population in the cirrhotic liver when compared with tumor tissue. These results indicated that in COVID-19-associated liver dysfunction and cell death, a viral infection of TROP2+ progenitors in the liver might significantly impair liver regeneration in patients with liver cirrhosis.

7.
Proc Natl Acad Sci U S A ; 118(6)2021 02 09.
Article in English | MEDLINE | ID: covidwho-1042803

ABSTRACT

Dendritic cells (DCs) and monocytes are crucial mediators of innate and adaptive immune responses during viral infection, but misdirected responses by these cells may contribute to immunopathology. Here, we performed high-dimensional flow cytometry-analysis focusing on mononuclear phagocyte (MNP) lineages in SARS-CoV-2-infected patients with moderate and severe COVID-19. We provide a deep and comprehensive map of the MNP landscape in COVID-19. A redistribution of monocyte subsets toward intermediate monocytes and a general decrease in circulating DCs was observed in response to infection. Severe disease coincided with the appearance of monocytic myeloid-derived suppressor cell-like cells and a higher frequency of pre-DC2. Furthermore, phenotypic alterations in MNPs, and their late precursors, were cell-lineage-specific and associated either with the general response against SARS-CoV-2 or COVID-19 severity. This included an interferon-imprint in DC1s observed in all patients and a decreased expression of the coinhibitory molecule CD200R in pre-DCs, DC2s, and DC3 subsets of severely sick patients. Finally, unsupervised analysis revealed that the MNP profile, alone, pointed to a cluster of COVID-19 nonsurvivors. This study provides a reference for the MNP response to SARS-CoV-2 infection and unravels mononuclear phagocyte dysregulations associated with severe COVID-19.


Subject(s)
COVID-19/immunology , Mononuclear Phagocyte System/immunology , SARS-CoV-2/immunology , Adult , COVID-19/epidemiology , COVID-19/metabolism , COVID-19/virology , Cytokines/immunology , Dendritic Cells/immunology , Female , Humans , Interferons/immunology , Male , Middle Aged , Monocytes/immunology , Mononuclear Phagocyte System/metabolism , Severity of Illness Index , Sweden
8.
Oncoimmunology ; 9(1): 1807836, 2020 08 25.
Article in English | MEDLINE | ID: covidwho-741761

ABSTRACT

Over the past 16 years, three coronaviruses (CoVs), severe acute respiratory syndrome CoV (SARS-CoV) in 2002, Middle East respiratory syndrome CoV (MERS-CoV) in 2012 and 2015, and SARS-CoV-2 in 2020, have been causing severe and fatal human epidemics. The unpredictability of coronavirus disease-19 (COVID-19) poses a major burden on health care and economic systems across the world. This is caused by the paucity of in-depth knowledge of the risk factors for severe COVID-19, insufficient diagnostic tools for the detection of SARS-CoV-2, as well as the absence of specific and effective drug treatments. While protective humoral and cellular immune responses are usually mounted against these betacoronaviruses, immune responses to SARS-CoV2 sometimes derail towards inflammatory tissue damage, leading to rapid admissions to intensive care units. The lack of knowledge on mechanisms that tilt the balance between these two opposite outcomes poses major threats to many ongoing clinical trials dealing with immunostimulatory or immunoregulatory therapeutics. This review will discuss innate and cognate immune responses underlying protective or deleterious immune reactions against these pathogenic coronaviruses.


Subject(s)
COVID-19/immunology , Host Microbial Interactions/immunology , SARS-CoV-2/immunology , COVID-19/diagnosis , COVID-19/virology , Humans , Immunity, Cellular , Immunity, Humoral , Middle East Respiratory Syndrome Coronavirus/immunology , Protective Factors , Risk Factors , SARS Virus/immunology , Severity of Illness Index
9.
Cell ; 182(6): 1401-1418.e18, 2020 09 17.
Article in English | MEDLINE | ID: covidwho-694669

ABSTRACT

Blood myeloid cells are known to be dysregulated in coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2. It is unknown whether the innate myeloid response differs with disease severity and whether markers of innate immunity discriminate high-risk patients. Thus, we performed high-dimensional flow cytometry and single-cell RNA sequencing of COVID-19 patient peripheral blood cells and detected disappearance of non-classical CD14LowCD16High monocytes, accumulation of HLA-DRLow classical monocytes (Human Leukocyte Antigen - DR isotype), and release of massive amounts of calprotectin (S100A8/S100A9) in severe cases. Immature CD10LowCD101-CXCR4+/- neutrophils with an immunosuppressive profile accumulated in the blood and lungs, suggesting emergency myelopoiesis. Finally, we show that calprotectin plasma level and a routine flow cytometry assay detecting decreased frequencies of non-classical monocytes could discriminate patients who develop a severe form of COVID-19, suggesting a predictive value that deserves prospective evaluation.


Subject(s)
Coronavirus Infections , Coronavirus , Pandemics , Pneumonia, Viral , Betacoronavirus , COVID-19 , Flow Cytometry , Humans , Leukocyte L1 Antigen Complex , Monocytes , Myeloid Cells , Prospective Studies , SARS-CoV-2
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