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1.
Emerg Microbes Infect ; 11(1): 1058-1071, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1752040

ABSTRACT

Safe, efficacious, and deployable vaccines are urgently needed to control COVID-19 in the large-scale vaccination campaigns. We report here the preclinical studies of an approved protein subunit vaccine against COVID-19, ZF2001, which contains tandem-repeat dimeric receptor-binding domain (RBD) protein with alum-based adjuvant. We assessed vaccine immunogenicity and efficacy in both mice and non-human primates (NHPs). ZF2001 induced high levels of RBD-binding and SARS-CoV-2 neutralizing antibody in both mice and non-human primates, and elicited balanced TH1/TH2 cellular responses in NHPs. Two doses of ZF2001 protected Ad-hACE2-transduced mice against SARS-CoV-2 infection, as detected by reduced viral RNA and relieved lung injuries. In NHPs, vaccination of either 25 µg or 50 µg ZF2001 prevented infection with SARS-CoV-2 in lung, trachea, and bronchi, with milder lung lesions. No evidence of disease enhancement was observed in both animal models. ZF2001 has been approved for emergency use in China, Uzbekistan, Indonesia, and Columbia. The high safety, immunogenicity, and protection efficacy in both mice and NHPs found in this preclinical study was consistent with the results in human clinical trials.


Subject(s)
COVID-19 Vaccines , COVID-19 , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , Carrier Proteins , Humans , Immunogenicity, Vaccine , Mice , Mice, Inbred BALB C , Primates , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics , Vaccines, Subunit
2.
EBioMedicine ; 75: 103803, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1587923

ABSTRACT

BACKGROUND: The Coronavirus Disease 2019 (COVID-19) pandemic has been a great threat to global public health since 2020. Although the advance on vaccine development has been largely achieved, a strategy to alleviate immune overactivation in severe COVID-19 patients is still needed. The NLRP3 inflammasome is activated upon SARS-CoV-2 infection and associated with COVID-19 severity. However, the processes by which the NLRP3 inflammasome is involved in COVID-19 disease remain unclear. METHODS: We infected THP-1 derived macrophages, NLRP3 knockout mice, and human ACE2 transgenic mice with live SARS-CoV-2 in Biosafety Level 3 (BSL-3) laboratory. We performed quantitative real-time PCR for targeted viral or host genes from SARS-CoV-2 infected mouse tissues, conducted histological or immunofluorescence analysis in SARS-CoV-2 infected mouse tissues. We also injected intranasally AAV-hACE2 or intraperitoneally NLRP3 inflammasome inhibitor MCC950 before SARS-CoV-2 infection in mice as indicated. FINDINGS: We have provided multiple lines of evidence that the NLRP3 inflammasome plays an important role in the host immune response to SARS-CoV-2 invasion of the lungs. Inhibition of the NLRP3 inflammasome attenuated the release of COVID-19 related pro-inflammatory cytokines in cell cultures and mice. The severe pathology induced by SARS-CoV-2 in lung tissues was reduced in Nlrp3-/- mice compared to wild-type C57BL/6 mice. Finally, specific inhibition of the NLRP3 inflammasome by MCC950 alleviated excessive lung inflammation and thus COVID-19 like pathology in human ACE2 transgenic mice. INTERPRETATION: Inflammatory activation induced by SARS-CoV-2 is an important stimulator of COVID-19 related immunopathology. Targeting the NLRP3 inflammasome is a promising immune intervention against severe COVID-19 disease. FUNDING: This work was supported by grants from the Bureau of Frontier Sciences and Education, CAS (grant no. QYZDJ-SSW-SMC005 to Y.G.Y.), the key project of the CAS "Light of West China" Program (to D.Y.) and Yunnan Province (202001AS070023 to D.Y.).


Subject(s)
COVID-19 , Lung , Macrophages , NLR Family, Pyrin Domain-Containing 3 Protein/immunology , SARS-CoV-2/immunology , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/immunology , Animals , COVID-19/genetics , COVID-19/immunology , COVID-19/pathology , Disease Models, Animal , Humans , Lung/immunology , Lung/pathology , Lung/virology , Macrophages/immunology , Macrophages/pathology , Macrophages/virology , Male , Mice , Mice, Knockout , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , SARS-CoV-2/genetics , THP-1 Cells
5.
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
6.
Cell Res ; 31(9): 1011-1023, 2021 09.
Article in English | MEDLINE | ID: covidwho-1315592

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global crisis, urgently necessitating the development of safe, efficacious, convenient-to-store, and low-cost vaccine options. A major challenge is that the receptor-binding domain (RBD)-only vaccine fails to trigger long-lasting protective immunity if used alone for vaccination. To enhance antigen processing and cross-presentation in draining lymph nodes (DLNs), we developed an interferon (IFN)-armed RBD dimerized by an immunoglobulin fragment (I-R-F). I-R-F efficiently directs immunity against RBD to DLNs. A low dose of I-R-F induces not only high titers of long-lasting neutralizing antibodies (NAbs) but also more comprehensive T cell responses than RBD. Notably, I-R-F provides comprehensive protection in the form of a one-dose vaccine without an adjuvant. Our study shows that the pan-epitope modified human I-R-F (I-P-R-F) vaccine provides rapid and complete protection throughout the upper and lower respiratory tracts against a high-dose SARS-CoV-2 challenge in rhesus macaques. Based on these promising results, we have initiated a randomized, placebo-controlled, phase I/II trial of the human I-P-R-F vaccine (V-01) in 180 healthy adults, and the vaccine appears safe and elicits strong antiviral immune responses. Due to its potency and safety, this engineered vaccine may become a next-generation vaccine candidate in the global effort to overcome COVID-19.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/immunology , Immunogenicity, Vaccine/immunology , Protein Binding/immunology , Protein Domains/immunology , SARS-CoV-2/immunology , Adolescent , Adult , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antiviral Agents/immunology , Cell Line , Chlorocebus aethiops , Double-Blind Method , Female , HEK293 Cells , Humans , Interferons/immunology , Macaca mulatta , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Middle Aged , Vaccination/methods , Vero Cells , Young Adult
7.
Innovation (N Y) ; 2(3): 100140, 2021 Aug 28.
Article in English | MEDLINE | ID: covidwho-1275768

ABSTRACT

A safe and effective vaccine is critical to combat the COVID-19 pandemic. Here, we developed a trimeric SARS-CoV-2 receptor-binding domain (RBD) subunit vaccine candidate that simulates the natural structure of the spike (S) trimer glycoprotein. Immunization with the RBD trimer-induced robust humoral and cellular immune responses, and a high level of neutralizing antibodies was maintained for at least 4.5 months. Moreover, the antibodies that were produced in response to the vaccine effectively cross-neutralized the SARS-CoV-2 501Y.V2 variant (B.1.351). Of note, when the vaccine-induced antibodies dropped to a sufficiently low level, only one boost quickly activated the anamnestic immune response, conferring full protection against a SARS-CoV-2 challenge in rhesus macaques without typical histopathological changes in the lung tissues. These results demonstrated that the SARS-CoV-2 RBD trimer vaccine candidate is highly immunogenic and safe, providing long-lasting, broad, and significant immunity protection in nonhuman primates, thereby offering an optimal vaccination strategy against COVID-19.

8.
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
9.
Nat Commun ; 12(1): 1346, 2021 03 01.
Article in English | MEDLINE | ID: covidwho-1111984

ABSTRACT

SARS-CoV-2 is the underlying cause for the COVID-19 pandemic. Like most enveloped RNA viruses, SARS-CoV-2 uses a homotrimeric surface antigen to gain entry into host cells. Here we describe S-Trimer, a native-like trimeric subunit vaccine candidate for COVID-19 based on Trimer-Tag technology. Immunization of S-Trimer with either AS03 (oil-in-water emulsion) or CpG 1018 (TLR9 agonist) plus alum adjuvants induced high-level of neutralizing antibodies and Th1-biased cellular immune responses in animal models. Moreover, rhesus macaques immunized with adjuvanted S-Trimer were protected from SARS-CoV-2 challenge compared to vehicle controls, based on clinical observations and reduction of viral loads in lungs. Trimer-Tag may be an important platform technology for scalable production and rapid development of safe and effective subunit vaccines against current and future emerging RNA viruses.


Subject(s)
COVID-19 Vaccines/therapeutic use , COVID-19/immunology , COVID-19/prevention & control , SARS-CoV-2/pathogenicity , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Blotting, Western , COVID-19/therapy , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunity, Cellular/physiology , Immunization, Passive , Immunohistochemistry , Macaca mulatta , Mice , Mice, Inbred BALB C , Microscopy, Electron , SARS-CoV-2/immunology
11.
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
12.
Zool Res ; 41(5): 517-526, 2020 Sep 18.
Article in English | MEDLINE | ID: covidwho-671953

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic continues to pose a global threat to the human population. Identifying animal species susceptible to infection with the SARS-CoV-2/ HCoV-19 pathogen is essential for controlling the outbreak and for testing valid prophylactics or therapeutics based on animal model studies. Here, different aged Chinese tree shrews (adult group, 1 year old; old group, 5-6 years old), which are close relatives to primates, were infected with SARS-CoV-2. X-ray, viral shedding, laboratory, and histological analyses were performed on different days post-inoculation (dpi). Results showed that Chinese tree shrews could be infected by SARS-CoV-2. Lung infiltrates were visible in X-ray radiographs in most infected animals. Viral RNA was consistently detected in lung tissues from infected animals at 3, 5, and 7 dpi, along with alterations in related parameters from routine blood tests and serum biochemistry, including increased levels of aspartate aminotransferase (AST) and blood urea nitrogen (BUN). Histological analysis of lung tissues from animals at 3 dpi (adult group) and 7 dpi (old group) showed thickened alveolar septa and interstitial hemorrhage. Several differences were found between the two different aged groups in regard to viral shedding peak. Our results indicate that Chinese tree shrews have the potential to be used as animal models for SARS-CoV-2 infection.


Subject(s)
Betacoronavirus/growth & development , Coronavirus Infections/diagnosis , Disease Models, Animal , Lung/pathology , Pneumonia, Viral/diagnosis , Tupaiidae/physiology , Age Factors , Animals , Betacoronavirus/physiology , COVID-19 , Coronavirus Infections/transmission , Coronavirus Infections/virology , Female , Humans , Lung/virology , Male , Pandemics , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , SARS-CoV-2 , Tupaiidae/virology , Virus Shedding/physiology
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