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1.
Cell Discov ; 8(1): 9, 2022 Feb 01.
Article in English | MEDLINE | ID: covidwho-1661959

ABSTRACT

Safe, effective, and economical vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are needed to achieve adequate herd immunity and end the pandemic. We constructed a novel SARS-CoV-2 vaccine, CoVac501, which is a self-adjuvanting peptide vaccine conjugated with Toll-like receptor 7 (TLR7) agonists. The vaccine contains immunodominant peptides screened from the receptor-binding domain (RBD) and is fully chemically synthesized. It has been formulated in an optimized nanoemulsion formulation and is stable at 40 °C for 1 month. In non-human primates (NHPs), CoVac501 elicited high and persistent titers of protective neutralizing antibodies against multiple RBD mutations, SARS-CoV-2 original strain, and variants (B.1.1.7 and B.1.617.2). Specific peptides booster immunization against the B.1.351 variant has also been shown to be effective in improving protection against B.1.351. Meanwhile, CoVac501 elicited the increase of memory T cells, antigen-specific CD8+ T-cell responses, and Th1-biased CD4+ T-cell immune responses in NHPs. Notably, at an extremely high SARS-CoV-2 challenge dose of 1 × 107 TCID50, CoVac501 provided near-complete protection for the upper and lower respiratory tracts of cynomolgus macaques.

2.
Signal Transduct Target Ther ; 6(1): 428, 2021 12 17.
Article in English | MEDLINE | ID: covidwho-1585884

ABSTRACT

SARS-CoV-2 infection-induced hyper-inflammation links to the acute lung injury and COVID-19 severity. Identifying the primary mediators that initiate the uncontrolled hypercytokinemia is essential for treatments. Mast cells (MCs) are strategically located at the mucosa and beneficially or detrimentally regulate immune inflammations. In this study, we showed that SARS-CoV-2-triggered MC degranulation initiated alveolar epithelial inflammation and lung injury. SARS-CoV-2 challenge induced MC degranulation in ACE-2 humanized mice and rhesus macaques, and a rapid MC degranulation could be recapitulated with Spike-RBD binding to ACE2 in cells; MC degranulation altered various signaling pathways in alveolar epithelial cells, particularly, the induction of pro-inflammatory factors and consequential disruption of tight junctions. Importantly, the administration of clinical MC stabilizers for blocking degranulation dampened SARS-CoV-2-induced production of pro-inflammatory factors and prevented lung injury. These findings uncover a novel mechanism for SARS-CoV-2 initiating lung inflammation, and suggest an off-label use of MC stabilizer as immunomodulators for COVID-19 treatments.


Subject(s)
COVID-19/metabolism , Cell Degranulation , Lung Injury/metabolism , Mast Cells/metabolism , Pulmonary Alveoli/metabolism , SARS-CoV-2/metabolism , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/genetics , Cell Line, Tumor , Female , Humans , Lung Injury/genetics , Lung Injury/virology , Macaca mulatta , Male , Mice, Inbred BALB C , Mice, Transgenic , Pulmonary Alveoli/virology , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
3.
Signal Transduct Target Ther ; 6(1): 328, 2021 09 01.
Article in English | MEDLINE | ID: covidwho-1392810

ABSTRACT

Understanding the pathological features of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in an animal model is crucial for the treatment of coronavirus disease 2019 (COVID-19). Here, we compared immunopathological changes in young and old rhesus macaques (RMs) before and after SARS-CoV-2 infection at the tissue level. Quantitative analysis of multiplex immunofluorescence staining images of formalin-fixed paraffin-embedded (FFPE) sections showed that SARS-CoV-2 infection specifically induced elevated levels of apoptosis, autophagy, and nuclear factor kappa-B (NF-κB) activation of angiotensin-converting enzyme 2 (ACE2)+ cells, and increased interferon α (IFN-α)- and interleukin 6 (IL-6)-secreting cells and C-X-C motif chemokine receptor 3 (CXCR3)+ cells in lung tissue of old RMs. This pathological pattern, which may be related to the age-related pro-inflammatory microenvironment in both lungs and spleens, was significantly correlated with the systemic accumulation of CXCR3+ cells in lungs, spleens, and peripheral blood. Furthermore, the ratio of CXCR3+ to T-box protein expression in T cell (T-bet)+ (CXCR3+/T-bet+ ratio) in CD8+ cells may be used as a predictor of severe COVID-19. These findings uncovered the impact of aging on the immunopathology of early SARS-CoV-2 infection and demonstrated the potential application of CXCR3+ cells in predicting severe COVID-19.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Cellular Microenvironment/immunology , Lung/immunology , Receptors, CXCR3/immunology , SARS-CoV-2/immunology , Angiotensin-Converting Enzyme 2/immunology , Animals , CD8-Positive T-Lymphocytes/pathology , COVID-19/pathology , Disease Models, Animal , Inflammation/immunology , Inflammation/pathology , Interferon-alpha/immunology , Interleukin-6/immunology , Lung/pathology , Lung/virology , Macaca mulatta , Male
5.
Zool Res ; 42(3): 350-353, 2021 May 18.
Article in English | MEDLINE | ID: covidwho-1231641

ABSTRACT

Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2), has become an unprecedented global health emergency. At present, SARS-CoV-2-infected nonhuman primates are considered the gold standard animal model for COVID-19 research. Here, we showed that northern pig-tailed macaques ( Macaca leonina, NPMs) supported SARS-CoV-2 replication. Furthermore, compared with rhesus macaques, NPMs showed rapid viral clearance in lung tissues, nose swabs, throat swabs, and rectal swabs, which may be due to higher expression of interferon (IFN)-α in lung tissue. However, the rapid viral clearance was not associated with good outcome. In the second week post infection, NPMs developed persistent or even more severe inflammation and body injury compared with rhesus macaques. These results suggest that viral clearance may have no relationship with COVID-19 progression and SARS-CoV-2-infected NPMs could be considered as a critically ill animal model in COVID-19 research.


Subject(s)
COVID-19/immunology , COVID-19/virology , Macaca nemestrina , SARS-CoV-2/immunology , Animals , Disease Models, Animal , Interferon-alpha/analysis , Interleukin-1beta/analysis , Interleukin-6/analysis , Lung/immunology , Lung/virology , Nose/virology , Pharynx/virology , RNA, Viral/analysis , Rectum/virology , SARS-CoV-2/genetics
6.
Zool Res ; 42(2): 161-169, 2021 Mar 18.
Article in English | MEDLINE | ID: covidwho-1070034

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease 2019 (COVID-19) continue to impact countries worldwide. At present, inadequate diagnosis and unreliable evaluation systems hinder the implementation and development of effective prevention and treatment strategies. Here, we conducted a horizontal and longitudinal study comparing the detection rates of SARS-CoV-2 nucleic acid in different types of samples collected from COVID-19 patients and SARS-CoV-2-infected monkeys. We also detected anti-SARS-CoV-2 antibodies in the above clinical and animal model samples to identify a reliable approach for the accurate diagnosis of SARS-CoV-2 infection. Results showed that, regardless of clinical symptoms, the highest detection levels of viral nucleic acid were found in sputum and tracheal brush samples, resulting in a high and stable diagnosis rate. Anti-SARS-CoV-2 immunoglobulin M (IgM) and G (IgG) antibodies were not detected in 6.90% of COVID-19 patients. Furthermore, integration of nucleic acid detection results from the various sample types did not improve the diagnosis rate. Moreover, dynamic changes in SARS-CoV-2 viral load were more obvious in sputum and tracheal brushes than in nasal and throat swabs. Thus, SARS-CoV-2 nucleic acid detection in sputum and tracheal brushes was the least affected by infection route, disease progression, and individual differences. Therefore, SARS-CoV-2 nucleic acid detection using lower respiratory tract samples alone is reliable for COVID-19 diagnosis and study.


Subject(s)
COVID-19 Testing/veterinary , COVID-19/diagnosis , SARS-CoV-2/genetics , Animals , Antibodies, Viral , Disease Models, Animal , Haplorhini , Humans , Longitudinal Studies , Pharynx/virology , Predictive Value of Tests , SARS-CoV-2/immunology , Specimen Handling , Sputum/virology
7.
Signal Transduct Target Ther ; 5(1): 294, 2020 12 24.
Article in English | MEDLINE | ID: covidwho-997816

ABSTRACT

Understanding the processes of immune regulation in patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is crucial for improving treatment. Here, we performed longitudinal whole-transcriptome RNA sequencing on peripheral blood mononuclear cell (PBMC) samples from 18 patients with coronavirus disease 2019 (COVID-19) during their treatment, convalescence, and rehabilitation. After analyzing the regulatory networks of differentially expressed messenger RNAs (mRNAs), microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) between the different clinical stages, we found that humoral immunity and type I interferon response were significantly downregulated, while robust T-cell activation and differentiation at the whole transcriptome level constituted the main events that occurred during recovery from COVID-19. The formation of this T cell immune response might be driven by the activation of activating protein-1 (AP-1) related signaling pathway and was weakly affected by other clinical features. These findings uncovered the dynamic pattern of immune responses and indicated the key role of T cell immunity in the creation of immune protection against this disease.


Subject(s)
COVID-19/genetics , Immunity, Humoral/genetics , T-Lymphocytes/metabolism , Transcriptome/genetics , COVID-19/epidemiology , COVID-19/pathology , Female , Humans , Immunity, Humoral/immunology , Leukocytes, Mononuclear/metabolism , Male , MicroRNAs , RNA, Long Noncoding/genetics , RNA-Seq , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , T-Lymphocytes/immunology , T-Lymphocytes/pathology , Transcription Factor AP-1/genetics
8.
Zool Res ; 41(5): 503-516, 2020 Sep 18.
Article in English | MEDLINE | ID: covidwho-709116

ABSTRACT

As of June 2020, Coronavirus Disease 2019 (COVID-19) has killed an estimated 440 000 people worldwide, 74% of whom were aged ≥65 years, making age the most significant risk factor for death caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. To examine the effect of age on death, we established a SARS-CoV-2 infection model in Chinese rhesus macaques ( Macaca mulatta) of varied ages. Results indicated that infected young macaques manifested impaired respiratory function, active viral replication, severe lung damage, and infiltration of CD11b + and CD8 + cells in lungs at one-week post infection (wpi), but also recovered rapidly at 2 wpi. In contrast, aged macaques demonstrated delayed immune responses with a more severe cytokine storm, increased infiltration of CD11b + cells, and persistent infiltration of CD8 + cells in the lungs at 2 wpi. In addition, peripheral blood T cells from aged macaques showed greater inflammation and chemotaxis, but weaker antiviral functions than that in cells from young macaques. Thus, the delayed but more severe cytokine storm and higher immune cell infiltration may explain the poorer prognosis of older aged patients suffering SARS-CoV-2 infection.


Subject(s)
Aging/immunology , Betacoronavirus/immunology , Coronavirus Infections/immunology , Cytokines/immunology , Macaca mulatta/immunology , Pneumonia, Viral/immunology , T-Lymphocytes/immunology , Age Factors , Aging/metabolism , Animals , Betacoronavirus/physiology , COVID-19 , Coronavirus Infections/veterinary , Coronavirus Infections/virology , Cytokines/metabolism , Inflammation/immunology , Inflammation/veterinary , Inflammation/virology , Lung/immunology , Lung/pathology , Lung/virology , Macaca mulatta/virology , Monkey Diseases/immunology , Monkey Diseases/virology , Pandemics/veterinary , Pneumonia, Viral/veterinary , Pneumonia, Viral/virology , SARS-CoV-2 , Severe Acute Respiratory Syndrome/immunology , Severe Acute Respiratory Syndrome/veterinary , Severe Acute Respiratory Syndrome/virology , T-Lymphocytes/metabolism , T-Lymphocytes/pathology , Viral Load/immunology , Viral Load/veterinary , Virus Replication/immunology
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