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BackgroundRising concerns over waning immunity and reduction in neutralizing activity against variants of concern (VOCs) have contributed to deploying booster doses by different strategies to tackle the COVID-19 pandemic. Preliminary findings from Phase I and II have shown that V-01, a recombinant fusion protein vaccine against COVID-19, exhibited favorable safety and immunogenicity profiles in 1060 adult participants of both younger and senior age. Herein, we aimed to assess the immunogenicity and safety for a booster dose in participants previously primed with a two-dose 10g V-01 regimen (day 0, 21) from phase I trial, providing reassuring data for necessity and feasibility of a homogenous booster dose. MethodsWe conducted a single-arm, open-label trial at the Guangdong Provincial Center for Disease Control and Prevention (Gaozhou, China). Forty-three eligible participants who were previously primed 4-5 months earlier with two-dose 10g V-01 regimen from phase I trial received booster vaccination. We primarily assessed the immunogenicity post-booster vaccination, measured by RBD-binding antibodies using ELISA and neutralizing activity against wild-type SARS-CoV-2 and emerging variants of concern (VOCs) using neutralization assays. We secondarily assessed the safety and reactogenicity of the booster vaccination. ResultsThe third dose of V-01 exhibited significant boosting effects of humoral immune response in participants primed with two-dose 10g V-01 regimen regarding both wild-type SARS-CoV-2 and VOCs. We observed a 60.4-folds increase in neutralizing titres against SARS-CoV-2 of younger adults, with GMTs of 17 (95%CI: 12-23) prior to booster vaccination in comparison to 1017 (95%CI: 732-1413) at day 14 post booster vaccination; and a 53.6-folds increase in that of older adults, with GMTs of 14 (95%CI: 9-20) before booster vaccination in comparison to 729(95%CI: 397-1339) at day 14 post-booster vaccination. The neutralizing titres against SARS-CoV-2 Delta strain also demonstrated a sharp increase from the day of pre booster vaccination to day 14 post booster vaccination, with GMTs of 11 (95%CI:8-15) versus 383 (95%CI:277-531) in younger adults (35.4-folds increase), and 6.5(95%CI: 5-8) versus 300(95%CI:142-631) in older adults (46.0-folds increase), respectively. We also observed a considerable and consistent increase of pseudovirus neutralizing titres against emerging VOCs from day 28 post second vaccination to day 14 post booster vaccination, with GMTs of 206 (95%CI:163-259) versus 607 (95%CI: 478-771) for Alpha strain, 54 (95%CI:38-77) versus 329 (95%CI: 255-425) for Beta strain, 219 (95%CI:157-306) versus 647 (95%CI: 484-865) for Delta strain. Our preliminary findings indicate a homogenous booster dose of V-01 was safe and well-tolerated, with overall adverse reactions being absent or mild-to-moderate in severity, and no grade 3 or worse AEs were related to booster vaccination. ConclusionsA homogenous booster immunization in participants receiving a primary series of two-dose V-01 elicited a substantial humoral immune response against wild-type SARS-CoV-2 and emerging VOCs, along with a favorable safety and reactogenicity profile. Our study provided promising data for a homogenous prime-boost strategy using recombinant protein vaccine to tackle the ongoing pandemic, potentially providing broad protection against emerging VOCs and overcoming waning immunity.
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COVID-19 is caused by a newly identified coronavirus, SARS-CoV-2, and has become a pandemic around the world. The illustration of the immune responses against SARS-CoV-2 is urgently needed for understanding the pathogenesis of the disease and its vaccine development. CD8+ T cells are critical for virus clearance and induce long lasting protection in the host. Here we identified specific HLA-A2 restricted T cell epitopes in the spike protein of SARS-CoV-2. Seven epitope peptides (n-Sp1, 2, 6, 7, 11, 13, 14) were confirmed to bind with HLA-A2 and potentially be presented by antigen presenting cells to induce host immune responses. Tetramers containing these peptides could interact with specific CD8+ T cells from convalescent COVID-19 patients, and one dominant epitope (n-Sp1) was defined. In addition, these epitopes could activate and generate epitope-specific T cells in vitro, and those activated T cells showed cytotoxicity to target cells. Meanwhile, all these epitopes exhibited high frequency of variations. Among them, n-Sp1 epitope variation 5L>F significantly decreased the proportion of specific T cell activation; n-Sp1 epitope 8L>V variant showed significantly reduced binding to HLA-A2 and decreased the proportion of n-Sp1-specific CD8+ T cell, which potentially contributes to the immune escape of SAR-CoV-2.
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BACKGROUND:Studies have shown that sacral nerve-root stimulation based on anodes block technique can effectively reconstruct the bladder voiding function of the rabbits with spinal cord injury. But the corresponding technology of stimulating electrode has not been reported so far. OBJECTIVE:To design and develop the stimulating electrodes matching with both rabbit sacral nerve roots and anodal blocking technique, to observe the ultrastructure and morphological change of rabbit sacral nerve roots which implanted in electrode stimulation for a long-term and to assess the safety of stimulating electrodes. METHODS:Thirty New Zealand rabbits were included, 10 rabbits were randomly selected from them and sacrificed after anesthesia, and then cut the anterior roots of bilateral S 2 and S 3 immediately;after measuring the diameter under the light microscope, the sleeve type stimulation electrode matched with the diameter was made. The remaining 20 rabbits were randomly divided into control group and implantation group, with 10 rabbits in each group. In the implantation group, the stimulating electrodes were implanted into the forepart of S 2 and S 3 nerve roots after anesthesia, and then sacrificed after fed for half a year for col ecting the samples. Then ultrastructure change of sacral nerve roots with the implantation was observed. RESULTS AND CONCLUSION:Structure of nerve cel s of sacral nerve roots remained in good condition under a light microscope after long-term implantation of the stimulating electrodes. No obvious degeneration of axons, no inflammatory infiltration and glial scar formation were observed. In the implantation group, myelins arranged closely without demyelination phenomenon, and there was no atrophy of neuronal nuclear, no nuclear sag, no increased nuclear decompression and heterochromatin in neurons under the light microscope. Immunohistochemical analysis showed, compared with the control group, there were no significant differences in the expressions of glial fibril ary acidic protein, Bax, Bcl-2 and Caspase-3 proteins of nerve roots in the implantation group. The stimulation electrode of rabbit sacral nerve root is developed successful y, that is, the implantation is simple and safe as it can be used for long-term implantation without histopathological changes and apoptosis.
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Objective To investigate the role of NF-KB binding element in regulation of NOD2. Methods Promoter region of NOD2 containing the NF-κB binding site was amplified by PCR from human genome DNA and correctly connected to the vector pEGFP-N3 which had been cut out promoter by restriction enzyme to obtain the GFP expression vector driven by human NOD2 gene promoter. The constructed plasmids were transiently transferred into cell line HeLa by LipofectAMINETM2000 and the GFP expression was ob- served by the inversion fluorescence microscope. The NF-κB binding site in the constructed vector pEGFP- N3-NOD2wt was deleted by the QuikChange site-directed mutagenesis kit. The recombinant plasmid mpEG- FP-N3-NOD2 was transiently transferred into cell line HeLa by LipofectAMINETM2000, and the GFP expres- sion was observed by the inversion fluorescence microscope. Results The constructed pEGFP-N3-NOD2wt plasmids and mpEGFP-N3-NOD2 were the same as the design confirmed by restriction digestion and se- quence analysis. The results of the cell transient transfection indicated that different strength of GEP ex- pressed by recombinant plasmids in HeLa cells could be observed. The GFP expression of constructed mpEGFP-N3-NOD2 was lower than that of pEGFP-N3-NOD2wt. Conclusion The GFP expression vector driven by human NOD2 gene promoter which contains the NF-κB binding site, and the site deleted plasmid were successfully constructed. The GFP expression of recombinant plasmid mpEGFP-N3-NOD2, deletion of the NF-KB binding site, was obviously weaken in HeLa. The results indicate that NF-KB binding element may play a positive role in regulation of NOD2 gene, which establishes favourable bases for further study on the mechanism of NOD2 gene expression and regulation.
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AIM and METHODS: To examine the relationship of glutathione S-transferase M1( GSTM 1) and T1( GSTT 1) with the occurrence of lung cancer, The case-control study was conducted among 161 lung cancer and 165 healthy controls. The genetic polymorphisms of GSTM1 and GSTT1 were detected with the method of multiplex polymerase chain reaction. Logistic regression analyses were used to assess the interaction of between different genotypes as well as between null genotypes and smoking. RESULTS: The frequences of GSTM 1 and GSTT 1 null genotypes had no obvious difference between lung cancer and healthy controls. In non-smoking subjects, the frequence of GSTM 1 null genotype was significantly different between lung cancer and healthy controls. Furthermore, GSTM 1 null genotype was significantly overrepresented in adenocarcinoma patients aged 60 or over, compared with controls.The results from interaction analyses showed although smoking and GSTM 1 deletion were associated with an increased risk of lung cancer, GSTM1 and GSTT 1 null genotypes combined with smoking did not have interaction effect on the risk of lung cancer. The risk for adnocarcinoma in the individuals at the age of 60 or over and in nonsmokers without GSTM1 gene but with GSTT1 functional genotype decreased by 48.5% and 45.3%, respectively. CONCLUSION: Our results suggest that GSTM1 deletion is an important host risk for lung cancer, and imply that GSTT1 functional genotype protects the old (aged 60 or over) and nonsmokers who are lack of GSTM1 gene from the risk of adenocarcinoma.
