Project description:The rapid spread of SARS-CoV-2 with its mutating strains has posed a global threat to safety during this COVID-19 pandemic. Thus far, there are 123 candidate vaccines in human clinical trials and more than 190 candidates in preclinical development worldwide as per the WHO on 1 October 2021. The various types of vaccines that are currently approved for emergency use include viral vectors (e.g., adenovirus, University of Oxford/AstraZeneca, Gamaleya Sputnik V, and Johnson & Johnson), mRNA (Moderna and Pfizer-BioNTech), and whole inactivated (Sinovac Biotech and Sinopharm) vaccines. Amidst the emerging cases and shortages of vaccines for global distribution, it is vital to develop a vaccine candidate that recapitulates the severe and fatal progression of COVID-19 and further helps to cope with the current outbreak. Hence, we present the preclinical immunogenicity, protective efficacy, and safety evaluation of a whole-virion inactivated SARS-CoV-2 vaccine candidate (ERUCoV-VAC) formulated in aluminium hydroxide, in three animal models, BALB/c mice, transgenic mice (K18-hACE2), and ferrets. The hCoV-19/Turkey/ERAGEM-001/2020 strain was used for the safety evaluation of ERUCoV-VAC. It was found that ERUCoV-VAC was highly immunogenic and elicited a strong immune response in BALB/c mice. The protective efficacy of the vaccine in K18-hACE2 showed that ERUCoV-VAC induced complete protection of the mice from a lethal SARS-CoV-2 challenge. Similar viral clearance rates with the safety evaluation of the vaccine in upper respiratory tracts were also positively appreciable in the ferret models. ERUCoV-VAC has been authorized by the Turkish Medicines and Medical Devices Agency and has now entered phase 3 clinical development (NCT04942405). The name of ERUCoV-VAC has been changed to TURKOVAC in the phase 3 clinical trial.
Project description:The BBIBP-CorV severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inactivated vaccine has been authorized for emergency use and widely distributed. We used single-cell transcriptome sequencing to characterize the dynamics of immune responses to the BBIBP-CorV inactivated vaccine. In addition to the expected induction of humoral immunity, we found that the inactivated vaccine induced multiple, comprehensive immune responses, including significantly increased proportions of CD16+ monocytes and activation of monocyte antigen presentation pathways; T cell activation pathway upregulation in CD8+ T cells, along with increased activation of CD4+ T cells; significant enhancement of cell-cell communications between innate and adaptive immunity; and the induction of regulatory CD4+ T cells and co-inhibitory interactions to maintain immune homeostasis after vaccination. Additionally, comparative analysis revealed higher neutralizing antibody levels, distinct expansion of naive T cells, a shared increased proportion of regulatory CD4+ T cells, and upregulated expression of functional genes in booster dose recipients with a longer interval after the second vaccination. Our research will support a comprehensive understanding of the systemic immune responses elicited by the BBIBP-CorV inactivated vaccine, which will facilitate the formulation of better vaccination strategies and the design of new vaccines.
Project description:Purpose: Construction of a SARSCoV2 vaccine TCR specific machine learning model using single-cell TCR technology sequencing Methods:PBMCs were isolated from peripheral venous blood of HLA-A2+ healthy donors. PBMCs were incubated with antibody cocktail and then RapidSpheres, then the magnet was applied and unbound CD8+ T cells were recovered from the supernatant. According to the above method of CD8+ T activation, CD8+ T cells specific for ancestral epitopes were obtained by stimulating with the corresponding mutant ancestral peptides. Activation-specific CD8+ T cells were labeled with tetramers-PE and CD8-APC and then sorted out by flow cytometer FACS Canto (BD). The following protocol describes surface protein staining with hashtag antibodies for protein detection outside of the single cell V(D)J signature barcoding technique for differentiating CD8+ T cells with different epitope specificities after mixing up samples. The following is the hashtag information corresponding to the ancestral epitopes of the mutant strains. B.1.1.7 corresponds to the ancestral epitope ORF1a 1707-16 , ORF1a 2225-34 , ORF1a 2230-38. B.1.617.2 corresponds to the ancestral epitope M 82-90 . B.1.617.3 corresponds to the ancestral epitope ORF1a 2240-49, ORF1a 3683-92 , and ancestral epitope S 2-11 of B.1.526.2 without labeled hashtag protein. Cell number and viability were checked after surface protein hashtag staining (cell viability > 80%). Then droplet-encapsulation single-cell sequencing experiments were performed, and 10,000 living single cells were loaded onto each of the Chromium Controller (10x Genomics). After droplet-encapsulation, single-cell cDNA synthesis, amplification and sequencing libraries were generated using Chromium Single Cell 5' Feature Barcode Library Kit (10x Genomics),Chromium The result showed the inactivated vaccine is less protective in older adults, who take longer to develop effective antibodies, and the TCR diversity of each epitope specific repertoire decreased in the elderly. In addition, we found inactivated vaccines could stimulate the proliferation of related B cells in the body, thereby reducing the diversity of BCR in the body. Compared with the young, the elderly is less likely to produce antibody related BCR clones and the same is true for TCR diversity. Conclusions: The result showed the inactivated vaccine is less protective in older adults, who take longer to develop effective antibodies, and the TCR diversity of each epitope specific repertoire decreased in the elderly. In addition, we found inactivated vaccines could stimulate the proliferation of related B cells in the body, thereby reducing the diversity of BCR in the body. Compared with the young, the elderly is less likely to produce antibody related BCR clones and the same is true for TCR diversity.
Project description:The objective of this study is to further analyze recombinant rabies virus-vectored SARS-CoV-2 vaccine, CORAVAX, as an effective COVID-19 vaccine strategy. CORAVAX has proven immunogenic and protective against SARS-CoV-2 in animal models. Here, we have screened adjuvants for the highest quality antibody titers, negated the concern of pre-existing rabies-vector immunity, and established its potential as a long-term COVID-19 vaccine. We have tested toll-like receptor 4 (TLR4) agonists, inflammasome activators, and alum adjuvants in CORAVAX and found TLR4-activating MPLA-AddaVax to have the greatest potential. We followed the humoral immune response to CORAVAX in mice with pre-existing rabies virus immunity and saw no significant differences compared to naive mice. We then followed the immune response to CORAVAX over several months and 1-year post-immunization. Mice maintained high antigen-specific serum antibody titers as well as long-lived antibody-secreting cells in the spleen and bone marrow. We believe this rabies-vector strategy combats the problem of waning immunity of other COVID-19 vaccines. These results together support CORAVAX's potential during the ongoing COVID-19 pandemic.
Project description:We report the development and evaluation of safety and immunogenicity of a whole virion inactivated (WVI) SARS-CoV-2 vaccine (BBV152), adjuvanted with aluminum hydroxide gel (Algel), or TLR7/8 agonist chemisorbed Algel. We used a well-characterized SARS-CoV-2 strain and an established Vero cell platform to produce large-scale GMP-grade highly purified inactivated antigen. Product development and manufacturing process were carried out in a BSL-3 facility. Immunogenicity and safety were determined at two antigen concentrations (3μg and 6μg), with two different adjuvants, in mice, rats, and rabbits. Our results show that BBV152 vaccine formulations generated significantly high antigen-binding and neutralizing antibody titers (NAb), at both concentrations, in all three species with excellent safety profiles. The inactivated vaccine formulation contains TLR7/8 agonist adjuvant-induced Th1-biased antibody responses with elevated IgG2a/IgG1 ratio and increased levels of SARS-CoV-2-specific IFN-γ+ CD4+ T lymphocyte response. Our results support further development for phase I/II clinical trials in humans.
Project description:BBIBP-CorV, an inactivated vaccine, has demonstrated safety, efficacy, and immunogenicity against COVID-19 in in-vitro studies and clinical trials. This study sought to comprehensively understand the development and duration of virus-specific antibodies and characterize the TCR-β repertoire changes in patients with BBIBP-CorV
Project description:BackgroundVaccination is the most effective way to prevent coronavirus disease 2019 (COVID-19). However, it is often less protective and does not significantly increase antibody levels, especially in individuals with impaired immune systems. Nevertheless, the immunocompetence can be enhanced using a natural immunomodulator, such as Dendrobium officinale aqueous extract (DoAE).MethodsTo determine whether DoAE promotes antibody production, we treated healthy volunteers with DoAE during COVID-19 vaccination. Meanwhile, the control volunteers were given a placebo (cornstarch) during the vaccination. Antibody levels were measured at three-week intervals in the DoAE and control groups.ResultsDoAE enhanced immunity and preserved immune cell homeostasis. However, the neutralizing antibody (nAb) levels in the DoAE group were lower than those in the control group. Analysis of the gut microbiota revealed that the abundance of anti-inflammatory flora was increased, while the pro-inflammatory flora was reduced in the DoAE group.ConclusionDoAE has immunomodulatory and anti-inflammatory properties. Therefore, DoAE has the potential for COVID-19 prophylaxis, treatment, and recovery from the adverse effects of COVID-19. However, its anti-inflammatory activity affects the production of nAbs. Thus, DoAE may not be recommended for consumption during COVID-19 vaccination.
Project description:Purpose:Comprehensively compared the adaptive immune response of SARS-CoV-2 inactivated vaccines in young and elderly. Methods:CD8+ T, CD4+ T and B cells were purified from PBMCs with EasySep Human positive/negative selection . PBMCs were incubated with antibody cocktail and then RapidSpheres, then the magnet was applied and unbound CD8+ T, CD4+ T and B cells were recovered from the supernatant. Briefly, the cells were stained with the corresponding CD8+ T, CD4+ T and B-cell antibodies for 30 minutes at 4°C in the dark, and the purity of the cells was detected separately by flow cytometry, and all could reach more than 95%. Total RNA was isolated from CD8+ T, CD4+ T and B cells of 3 young and older people using TRIzol Reagent (Invitrogen) (7-days post second vaccination dose) . RNA purity was checked by the NanoPhotomerer spectrophotometer (IMPLEN), and integrity was assessed using the RNA Nano 6000 Assay Kit of the Bioanalyzer 2100 system (Agilent Technologies). Then cDNA libraries were constructed using 0.1 µg RNA per sample with the NEBNext UltraTM RNA Library Prep Kit for Illumina (NEB) following manufacturer’s recommendations and index codes were added to attribute sequences to each sample. The clustering of the index-coded samples was performed on a cBot Cluster Generation System using TruSeq PE Cluster Kit v3-cBot-HS (Illumia). After cluster generation, the library preparations were sequenced on an Illumina Novaseq platform and 250 bp paired-end reads were generated. The result showed the inactivated vaccine is less protective in older adults, who take longer to develop effective antibodies, and the TCR diversity of each epitope specific repertoire decreased in the elderly. In addition, we found inactivated vaccines could stimulate the proliferation of related B cells in the body, thereby reducing the diversity of BCR in the body. Compared with the young, the elderly is less likely to produce antibody related BCR clones and the same is true for TCR diversity. Conclusions: The result showed the inactivated vaccine is less protective in older adults, who take longer to develop effective antibodies, and the TCR diversity of each epitope specific repertoire decreased in the elderly. In addition, we found inactivated vaccines could stimulate the proliferation of related B cells in the body, thereby reducing the diversity of BCR in the body. Compared with the young, the elderly is less likely to produce antibody related BCR clones and the same is true for TCR diversity.
Project description:ObjectivesDuring COVID-19 pandemic, the absence of immunity in the population left them susceptible to infection with SARS-CoV-2; healthcare workers (HCWs) being in the highest risk group. This study intends to assess and follow up the humoral immunity in HCWs vaccinated with an inactive virus vaccine (CoronaVac).Study designThis is a prospective observational study.MethodsA total of 1072 HCWs were investigated for the presence of immunoglobulin G antibodies to the receptor-binding domain of the S1 subunit of the spike protein of SARS-CoV-2 after vaccination. Blood samples were obtained after 28 days of the first dose, 21 days of the second dose, and 3 months after the second dose. Detection of antispike antibodies was performed by the chemiluminescent microparticle immunoassay method (SARS-CoV-2 IgG II Quant, Abbott, Ireland). The results greater than or equal to the cutoff value of 50.0 AU/mL were reported as positive.ResultsFour weeks after the first dose of vaccine, antispike antibodies were detected in 834/1072 (77.8%) of HCWs. Seropositivity was higher among females (84.6%) than males (70.6% p < 0.001) and was found to be highest in both women and men between the ages of 18-34 years. Antispike antibodies were detected in 1008 of 1012 (99.6%) after 21 days of the second dose and in 803 of 836 (96.1%) after 3 months of the second dose.ConclusionsCoronaVac was found to be highly immunogenic after two consecutive doses performed 28 days apart to HCWs; however, the immunogenicity declined significantly (p < 0.001) after 3 months following the second dose of vaccine.
Project description:The overall success of worldwide mass vaccination in limiting the negative effect of the COVID-19 pandemics is inevitable, however, recent SARS-CoV-2 variants of concern, especially Omicron and its sub-lineages, efficiently evade humoral immunity mounted upon vaccination or previous infection. Thus, it is an important question whether these variants, or vaccines against them, induce anti-viral cellular immunity. Here we show that the mRNA vaccine BNT162b2 induces robust protective immunity in K18-hACE2 transgenic B-cell deficient (μMT) mice. We further demonstrate that the protection is attributed to cellular immunity depending on robust IFN-γ production. Viral challenge with SARS-CoV-2 Omicron BA.1 and BA.5.2 sub-variants induce boosted cellular responses in vaccinated μMT mice, which highlights the significance of cellular immunity against the ever-emerging SARS-CoV-2 variants evading antibody-mediated immunity. Our work, by providing evidence that BNT162b2 can induce significant protective immunity in mice that are unable to produce antibodies, thus highlights the importance of cellular immunity in the protection against SARS-CoV-2.