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: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: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: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: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:The worldwide outbreak of SARS-CoV-2, severe acute respiratory syndrome coronavirus 2 as a novel human coronavirus, was the worrying news at the beginning of 2020. Since its emergence complicated more than 870,000 individuals and led to more than 43,000 deaths worldwide. Considering to the potential threat of a pandemic and transmission severity of it, there is an urgent need to evaluate and realize this new virus's structure and behavior and the immunopathology of this disease to find potential therapeutic protocols and to design and develop effective vaccines. This disease is able to agitate the response of the immune system in the infected patients, so ARDS, as a common consequence of immunopathological events for infections with Middle East respiratory syndrome coronavirus (MERS-CoV), SARS-CoV, and SARS-CoV-2, could be the main reason for death. Here, we summarized the immune response and immune evasion characteristics in SARS-CoV, MERS-CoV, and SARS-CoV-2 and therapeutic and prophylactic strategies with a focus on vaccine development and its challenges.
Project description:The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) threatens global public health. The development of a vaccine is urgently needed for the prevention and control of COVID-19. Here, we report the pilot-scale production of an inactivated SARS-CoV-2 vaccine candidate (BBIBP-CorV) that induces high levels of neutralizing antibodies titers in mice, rats, guinea pigs, rabbits, and nonhuman primates (cynomolgus monkeys and rhesus macaques) to provide protection against SARS-CoV-2. Two-dose immunizations using 2 μg/dose of BBIBP-CorV provided highly efficient protection against SARS-CoV-2 intratracheal challenge in rhesus macaques, without detectable antibody-dependent enhancement of infection. In addition, BBIBP-CorV exhibits efficient productivity and good genetic stability for vaccine manufacture. These results support the further evaluation of BBIBP-CorV in a clinical trial.
Project description:Since the outbreak of COVID-19, a variety of vaccine platforms have been developed. Amongst these, inactivated vaccines have been authorized for emergency use or conditional marketing in many countries. To further enhance the protective immune responses in populations that have completed vaccination regimen, we investigated the immunogenic characteristics of different vaccine platforms and tried homologous or heterologous boost strategy post two doses of inactivated vaccines in a mouse model. Our results showed that the humoral and cellular immune responses induced by different vaccines when administered individually differ significantly. In particular, inactivated vaccines showed relatively lower level of neutralizing antibody and T cell responses, but a higher IgG2a/IgG1 ratio compared with other vaccines. Boosting with either recombinant subunit, adenovirus vectored or mRNA vaccine after two-doses of inactivated vaccine further improved both neutralizing antibody and Spike-specific Th1-type T cell responses compared to boosting with a third dose of inactivated vaccine. Our results provide new ideas for prophylactic inoculation strategy of SARS-CoV-2 vaccines.