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The coronavirus SARS-CoV-2 has mutated quickly and caused significant global damage. This study characterizes two mRNA vaccines ZSVG-02 (Delta) and ZSVG-02-O (Omicron BA.1), and associating heterologous prime-boost strategy following the prime of a most widely administrated inactivated whole-virus vaccine (BBIBP-CorV). The ZSVG-02-O induces neutralizing antibodies that effectively cross-react with Omicron subvariants following an order of BA.1>BA.2>BA.4/5. In naive animals, ZSVG-02 or ZSVG-02-O induce humoral responses skewed to the vaccines targeting strains, but cellular immune responses cross-react to all variants of concern (VOCs) tested. Following heterologous prime-boost regimes, animals present comparable neutralizing antibody levels and superior protection across all VOCs. Single-boost only generated ancestral and omicron dual-responsive antibodies, probably by "recall" and "reshape" the prime immunity. New Omicron-specific antibody populations, however, appeared only following the second boost with ZSVG-02-O. Overall, our results support a heterologous boost with ZSVG-02-O, providing the best protection against current VOCs in inactivated virus vaccine- primed populations.
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SARS-CoV-2 variants of concern (VOCs), especially the latest Omicron, have exhibited severe antibody evasion. Broadly neutralizing antibodies with high potency against Omicron are urgently needed for understanding working mechanisms and developing therapeutic agents. In this study, we characterized previously reported F61, which was isolated from convalescent patients infected with prototype SARS-CoV-2, as a broadly neutralizing antibody against all VOCs including Omicron BA.1, BA.1.1, BA.2, BA.3 and BA.4 sublineages by utilizing antigen binding and cell infection assays. We also identified and characterized another broadly neutralizing antibody D2 with epitope distinct from that of F61. More importantly, we showed that a combination of F61 with D2 exhibited synergy in neutralization and protecting mice from SARS-CoV-2 Delta and Omicron BA.1 variants. Cryo-EM structures of the spike-F61 and spike-D2 binary complexes revealed the distinct epitopes of F61 and D2 at atomic level and the structural basis for neutralization. Cryo-EM structure of the Omicron-spike-F61-D2 ternary complex provides further structural insights into the synergy between F61 and D2. These results collectively indicated F61 and F61-D2 cocktail as promising therapeutic antibodies for combating SARS-CoV-2 variants including diverse Omicron sublineages.
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To investigate the duration of humoral immune response in convalescent coronavirus disease 2019 (COVID-19) patients, we conduct a 12-month longitudinal study through collecting a total of 1,782 plasma samples from 869 convalescent plasma donors in Wuhan, China and test specific antibody responses. The results show that positive rate of IgG antibody against receptor-binding domain of spike protein (RBD-IgG) to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the COVID-19 convalescent plasma donors exceeded 70% for 12 months post diagnosis. The level of RBD-IgG decreases with time, with the titer stabilizing at 64.3% of the initial level by the 9th month. Moreover, male plasma donors produce more RBD-IgG than female, and age of the patients positively correlates with the RBD-IgG titer. A strong positive correlation between RBD-IgG and neutralizing antibody titers is also identified. These results facilitate our understanding of SARS-CoV-2-induced immune memory to promote vaccine and therapy development.
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Rabies remains endemic in China and continues to pose a major threat to public health with a nearly 100 % case fatality rate in humans. We confirmed a case of human rabies in Wuhan, in May 2018. The patient had got a dog bite wound 3 years before symptoms of confusion, hydrophobia, and photophobia onset. On May 14, our laboratory confirmed that the patient was infected with a rabies virus that circulates in dogs in China and died on May 24, two weeks later after admission. Complete glycoprotein gene sequences determined for this isolate indicated the source of a RABV infection was dog-related RABV variants.
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Objective:To analyze the molecular characteristics of Echovirus 11 (Echo11) strains isolated in Xiangyang, Hubei Province from 2016 to 2017 based on the sequences of VP1 gene.Methods:Rectal and throat swab specimens were collected from children with hand, foot and mouth disease (HFMD) in Xiangyang from 2016 to 2017. Echo11 strains were detected by real-time reverse transcriptase PCR (RT-PCR) and isolated after cultured in human rhabdosarcoma (RD) cells. The VP1 regions of Echo11 strains isolated from RD cells and the whole genomes of three representative Echo11 strains were amplified by conventional RT-PCR and the sequences were analyzed. DNAStar7.0 (MegAlign) and MEGA6.0 (Data) were used to analyze the homology and mutation sites in nucleotide and amino acid sequences. Neighbor-joining method was used to construct phylogenetic trees. Recombination analysis was performed with SimPlot software (BootScanning).Results:A total of 11 Echo11 strains were isolated from 3 494 HFMD cases, accounting for 0.31%. They were highly homologous in the VP1 gene. These strains shared 98.4%-100.0% homology in nucleotide sequences and 98.3%-100.0% homology in amino acid sequences. The homology between the 11 Echo11 strains and the prototype strain (Echo11/Gregory, X80059) was 73.9%-74.8% in nucleotide sequences and 87.7%-88.7% in amino acid sequences. All of the Echo11 strains circulating in Xiangyang were classified into lineage D, having a similarity to the strains circulating in some regions of mainland China since 2013. In multiple regions of the genome, the Echo11 strains isolated in Xiangyang were highly similar to the Henan Echo1 strains in 2010 and the Hubei Echo6 strains in 2015, suggesting there was recombination within the genome of Echo11 strains in Xiangyang.Conclusions:The Echo11 strains circulating in Xiangyang from 2016 to 2017 belonged to lineage D and were recombinant strains.
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Currently, there are no approved specific antiviral agents for 2019 novel coronavirus disease (COVID-19). In this study, ten severe patients confirmed by real-time viral RNA test were enrolled prospectively. One dose of 200 mL convalescent plasma (CP) derived from recently recovered donors with the neutralizing antibody titers above 1:640 was transfused to the patients as an addition to maximal supportive care and antiviral agents. The primary endpoint was the safety of CP transfusion. The second endpoints were the improvement of clinical symptoms and laboratory parameters within 3 days after CP transfusion. The median time from onset of illness to CP transfusion was 16.5 days. After CP transfusion, the level of neutralizing antibody increased rapidly up to 1:640 in five cases, while that of the other four cases maintained at a high level (1:640). The clinical symptoms were significantly improved along with increase of oxyhemoglobin saturation within 3 days. Several parameters tended to improve as compared to pre-transfusion, including increased lymphocyte counts (0.65x109/L vs. 0.76x109/L) and decreased C-reactive protein (55.98 mg/L vs. 18.13 mg/L). Radiological examinations showed varying degrees of absorption of lung lesionswithin 7 days. The viral load was undetectable after transfusion in seven patients who had previous viremia. No severe adverse effects were observed. This study showed CP therapy was welltolerated and could potentially improve the clinical outcomes through neutralizing viremia in severe COVID-19 cases. The optimal dose and time point, as well as the clinical benefit of CP therapy, needs further investigation in larger well-controlled trials. Significance StatementCOVID-19 is currently a big threat to global health. However, no specific antiviral agents are available for its treatment. In this work, we explored the feasibility of convalescent plasma (CP) transfusion to rescue severe patients. The results from 10 severe adult cases showed that one dose (200 mL) of CP was welltolerated and could significantly increase or maintain the neutralizing antibodies at a high level, leading to disappearance of viremia in 7 days. Meanwhile, clinical symptoms and paraclinical criteria rapidly improved within 3 days. Radiological examination showed varying degrees of absorption of lung lesions within 7 days. These results indicate that CP can serve as a promising rescue option for severe COVID-19 while the randomized trial is warranted.
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Objective To detect and analyze enteroviruses causing suspected aseptic meningitis in a kindergarten in Jinhua City, Zhejiang Province. Methods Viral RNA was extracted from samples and cDNA was prepared by reverse transcription. PCR was performed to amplify the partial sequences of the 5′-untranslated region ( UTR) and VP1 gene of enteroviruses. Serotypes of the viruses were determined by com-paring the homology between the partial sequences of VP1 gene. Phylogenetic tree of the partial VP1 se-quences was constructed using MEGA6. Results This study included seven patients and twenty-six asymp-tomatic students. Coxsakievirus A10 (CV-A10) was detected in 48. 5％ of the students and echovirus 6 (Echo 6) in 21. 2％. Besides, 12. 1％ of the students might be co-infected by the two viruses. Among the seven patients, six were infected by CV-A10 and the other one might have co-infection. According to the phylogenetic analysis, CV-A10 strains detected in this study were closely related to those isolated in China in recent years, including the strains isolated in Xiamen in 2015 and Yunnan in 2017, while the Echo 6 strains were phylogenetically related to those isolated in Yunnan, Guangzhou and Shandong in 2014. Conclusions CV-A10 and Echo 6 were detected in the cases with suspected aseptic meningitis and had close phylogenetic relationships to the strains appeared in China in recent years.
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Objective@#To construct the prokaryotic plasmid expressing the recombinant protein Coxsackie virus A6 VP1 or VP2 and prepare the antiserum of rabbit anti-CVA6 VP1 or anti-CVA6 VP2.@*Methods@#CVA6 VP1and VP2 gene fragments were amplified by reverse transcription PCR and inserted into the prokaryotic expression vectors. The recombinant plasmids were expressed in E. coli BL21 (DE3). After induction with Isopropyl β-D-Thiogalactoside (IPTG), the fusion proteins were obtained, and then purified by SDS-PAGE electrophoresis and gel extraction. The polyclonal antibodies were prepared by immunizing rabbits with the fusion proteins and analyzed with Western blot(WB) and indirect immunofluorescence assay(IFA).@*Results@#The prokaryotic expression vector of CVA6 VP1 or VP2 was confirmed by PCR, double enzyme digestion and sequencing. CVA6 VP1 and VP2 fusion proteins with high purity were obtained. WB and IFA were used to identify polyclonal antibodies.@*Conclusions@#The CVA6 VP1 and VP2 prokaryotic expression vectors were successfully constructed, and the recombinant CVA6 VP1 and VP2 proteins and their corresponding polyclonal antibodies were obtained.
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In the present study, the effect of serum (fetal bovine serum, FBS) on cellular uptake behaviors of DNA tetrahedron (TDNs) was investigated.Fluorescence-labeled TDNs were synthesized by self-assembly and purified with HPLC to achieve TDNs product with purity of 95%.By means of flow cytometry and confocal microscopy, the kinetics of TDNs endocytosis in HeLa cells in the presence or absence of FBS was compared.The results showed that TDNs remained intact in complete medium and cell lysate for more than 12 hours.FBS increased the amount of internalized TDNs in HeLa cells, whereas it did not change the route of caveolin-dependent endocytosis.Herein, our study provided a new insight into the effects of biomolecules on the interaction between cells and DNA nanostructures, which helped the future development of DNA-based intracellular nanocarriers.
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Objective: To analyze the influence of long-term swimming training on spatial learning-memory in rats and its relationship with cyclic adenosine monophosphate(cAMP) and cyclic guanosine monophosphate(cGMP) signal transduction pathway. Method: After 3 times adaptable swimming exercises (30min each time), 40 male SD rats were divided into 2 groups: control group (CR, n=20) and exercises, group (TR, n=20). CR group didn't swim, and TR group swam without burden (6 times/week, 60 min each time). After 8 weeks training, 10 rats were selected from both groups respectively for examing of Morris water maze test. Radioimmunoassay was used to measure the levels of cAMP and cGMP in hippocampus and prefrontal cortex of rats. Result: ①Compared with CR group, in TR group learning-memory improved in a certain extent: ②Compared with CR group, in TR group, the level of cAMP in hippocampus enhanced very obviously (P＜0.01), the cAMP/cGMP ratio enhanced obviously (P＜0.05); in prefrontal cortex the levels of cAMP and cAMP/cGMP ratio enhanced obviously (P＜0.05). Conclusion: Swimming training for 8 weeks improved the spatial learning-memory of rats in a certain extent, and elevated the level of cAMP and cAMP/cGMP ratio in hippocampus and prefrontal cortex of rats obviously. It is suggested that exercises might affect learning-memory by cAMP and cGMP signal transduction pathway.
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0.05),but the 24h urine zinc level increased markedly(P
