Objective:To construct a novel respiratory syncytial virus (RSV) vaccine based on a recombinant influenza virus vector and evaluate its immune protective effects in mice.Methods:A recombinant H1N1 influenza A virus (IAV) expressing the extracellular domain (Gecto) of RSV A2 G protein was constructed and rescued, named as PR8NAGecto/WSN. After in vitro verification of the Gecto expression and PR8NAGecto/WSN growth kinetics, a single dose of PR8NAGecto/WSN was used to immunize BALB/c mice through intranasal administration to evaluate the efficacy of PR8NAGecto/WSN by assessing humoral (IgG, neutralizing antibody), mucosal (IgA) and cellular immunity (IFN-γ ELISPOT). Four weeks after immunization, the mice were challenged with RSV A2 or RSV B9320 to evaluate the protective effects of PR8NAGecto/WSN by analyzing mouse body weight changes, lung tissue virus titers and pathological changes. Results:A single-dose intranasal immunization with PR8NAGecto/WSN induced robust humoral, mucosal and cellular immunity in mice. Moreover, the mice in the immunized group had lower lung virus loads and mild lung pathological damages following the challenge with RSV A or RSV B subtype as compared with the control group.Conclusions:A single-dose intranasal immunization with PR8NAGecto/WSN induces robust immunity and provide protection against RSV A and B challenges in mice. This study provides new ideas and reference for the development of novel mucosal vaccines against RSV.

Objective:To investigate the relationship between positive asthma prediction index (API) and single nucleotide polymorphisms (SNPs) of interleukin (IL-13), IL-4, β 2 adrenergic receptor (ADRB2), and type I Fc ε receptor β (FcER1B) genes in asthmatic children.Methods:A prospective study was conducted on 102 asthmatic children under 5 years old admitted to Zhongshan Boai Hospital and Foshan First People′s Hospital (51 cases were API positive and 51 cases were API negative) from January 2020 to August 2023. Oral and buccal mucosal exfoliated cells were collected from the children, and genomic DNA was extracted using magnetic bead method. Four gene loci (IL-13 rs20541, IL-4 rs2243250, ADRB2 rs1042713, FcER1B rs569108) were genotyped using a matrix assisted laser desorption ionization time-of-flight mass spectrometer. Logistic regression analysis was used to evaluate the correlation between SNP typing at these four gene loci and API positivity in asthmatic children.Results:There was a statistically significant difference in the SNP typing and allele distribution frequency of IL-13 rs20541, IL-4 rs2243250, ADRB2 rs1042713, FcER1B rs569108 between the API positive and API negative groups of wheezing children (all P<0.05). Among API positive children, the proportion of IL-13 rs20541 site was higher in GG type, the proportion of IL-4 rs2243250 site was higher in TT type, the proportion of ADRB2 rs1042713 site was higher in AG type, and the proportion of FcER1B rs569108 site was higher in AA type; The results of logistic regression analysis showed that IL-13 rs20541 GG type, IL-4 rs2243250 TT type, FcER1B rs569108 AA type were associated with the risk of API positivity in asthmatic children (all P<0.05). Conclusions:IL-13, IL-4, and FcER1B genes are risk genes for the development of API positive wheezing in children under 5 years old. SNP typing of these genes can be used to evaluate the risk of API positivity in clinical practice.

Objective:To accurately ascertain the whole genome sequencing and the composition of open reading frames (ORFs) of non-replicating Tiantan strain of vaccinia virus (NTV) using next-generation long-read sequencing technology.Methods:NTV, obtained from our laboratory stock, was amplified and purified on chicken embryo fibroblast cells(CEFs), and the full-length genomic nucleic acid of NTV was extracted. The PacBio HiFi sequencing platform was utilized for de novo assembly to obtain the complete genomic sequence of NTV. Using a homology annotation strategy, we identified its ORF composition and compared it with known non-replicating vaccinia virus strains. Results:The total length of NTV′s genome was 171 729 bp, with a GC content of 33%. Its unique inverted terminal repeat (ITR) region comprised hairpin structures, two tandem repeat regions, and three non-repeat regions. NTV contained 166 ORFs, with major differences observed in the ITR and its surrounding regions when compared to MVA-BN and NYVAC. These three strains shared a common set of 138 ORFs. NTV encoded six unique ORFs related to virus evasion of host antiviral response.Conclusions:This study accurately determines the whole genome sequencing and ORFs composition of NTV, and reveals its similarities and differences with other replication-deficient vaccinia virus strains, which pave a way for the development and application of the next generation of monkeypox vaccines and novel viral vectors.

Objective: To explore the association between light intensity physical activity (LPA) and sedentary behavior (SB) with body composition, so as to provide data references for improving adolescent physical health. Methods: From August 2020 to January 2021, general information of 694 students in grade one of a high school in Foshan City was collected, and the 24 hour activity behavior and body composition of the students were measured objectively by triaxial accelerometer and bioelectrical impedance tester. Dual component multivariate regression and dual compositional isotemporal substitution model were used to explore the relationship between LPA and SB and body composition. Results: LPA was associated with lower fat relative dominance (FRD) (male weekends FRD=-21.44%, female weekly FRD=-17.83%, weekdays FRD=-18.27%, P <0.05), and LPA was also associated with higher muscle relative dominance (MRD) and bone relative dominance (BRD) (male weekends MRD=12.78%, BRD= 12.87 %; female weekly MRD=11.64%, BRD=9.01%; female weekdays MRD=12.02%, BRD=9.23%, P <0.05). Replacing sedentary behavior (SB) with 10 minutes of LPA could reduce fat proportion [male:weekly -0.15(-0.26--0.04), weekdays -0.12 (-0.22--0.02); female:weekly -0.18(-0.27--0.08), weekdays -0.16(-0.25--0.07)) and increase muscle proportion (male:weekly 0.14(0.03-0.24), weekdays 0.11(0.02-0.21); female:weekly 0.17(0.07-0.26), weekdays 0.15(0.07-0.24)]. Conclusion Interrupting continuous SB with LPA can serve as an intervention measure to promote physical health and fitness in adolescents. School should encourage students to engage in frequent LPA during breaks and after school activities, while avoiding prolonged SB.

Objective:To construct recombinant influenza viruses expressing Gaussia luciferase (Gluc) with different influenza virus backbones and analyze their growth characteristics, genetic stability, ability to express Gluc and in vitro anti-influenza drug activity. Methods:The C-terminal of PR8NA was modified by inserting the porcine teschovirus-2A autocleavage peptide (P2A) and the Gluc-coding gene. Recombinant viruses, PR8NAGluc/PR8 and PR8NAGluc/WSN, were rescued using the eight-plasmid system of influenza virus reverse genetics, with seven plasmids derived from A/Puerto Rico/8/34(PR8) (H1N1) and A/WSN/1933 (WSN) H1N1. The genetic stability of the recombinant viruses was verified by RT-PCR. The fluorescence activity and the growth kinetics of the two recombinant viruses were compared. The correlation between the fluorescence activity of PR8NAGluc/WSN and median tissue culture infective dose (TCID 50), and the anti-drug activity of PR8NAGluc/WSN against oseltamivir, favipiravir, and Lianhua Qingwen in vitro were also analyzed. Results:The Gluc-expressing recombinant viruses constructed using PR8 and WSN backbones were successfully rescued by reverse genetics. Compared with the PR8 backbone, the WSN backbone significantly improved the fluorescence activity of Gluc. Moreover, the PR8NAGluc/WSN virus expressed stably in embryonated egg, and its replication kinetics was slightly lower than that of wild type. The fluorescence activity of PR8NAGluc/WSN virus had a good correlation with its TCID 50. The PR8NAGluc/WSN virus was sensitive to oseltamivir, favipiravir and Lianhua Qingwen. Conclusions:The recombinant virus with a WSN backbone exhibited higher fluorescence expression intensity as compared with the recombinant virus with a PR8 backbone. This study provided reference for high-throughput screening of anti-influenza drugs and the development of influenza virus vector vaccines.

Coronavirus disease 2019 (COVID-19) has continued to spread globally since late 2019, representing a formidable challenge to the world's healthcare systems, wreaking havoc, and spreading rapidly through human contact. With fever, fatigue, and a persistent dry cough being the hallmark symptoms, this disease threatened to destabilize the delicate balance of our global community. Rapid and accurate diagnosis of COVID-19 is a prerequisite for understanding the number of confirmed cases in the world or a region, and an important factor in epidemic assessment and the development of control measures. It also plays a crucial role in ensuring that patients receive the appropriate medical treatment, leading to optimal patient care. Reverse transcription-polymerase chain reaction (RT-PCR) technology is currently the most mature method for detecting viral nucleic acids, but it has many drawbacks. Meanwhile, a variety of COVID-19 detection methods, including molecular biological diagnostic, immunodiagnostic, imaging, and artificial intelligence methods have been developed and applied in clinical practice to meet diverse scenarios and needs. These methods can help clinicians diagnose and treat COVID-19 patients. This review describes the variety of such methods used in China, providing an important reference in the field of the clinical diagnosis of COVID-19.
Humans ; Artificial Intelligence ; China ; COVID-19/diagnosis* ; COVID-19 Testing

Objective:To develop a recombinase-aided amplification (RAA)-clustered regularly interspaced short palindromic repeats(CRISPR)/Cas12a-based nucleic acid assay for monkeypox virus with high specificity and sensitivity.Methods:RAA primers and CRISPR RNA (crRNA) were designed based on the known conserved regions of the monkeypox virus gene and synthesized, and specific crRNAs were screened using fluorescence detection. The sensitivity and specificity of the detection system were evaluated.Results:An RAA-CRISPR/Cas12a-based nucleic acid assay for monkeypox virus was developed with a sensitivity of 2.5 copies/reaction and high specificity without cross-reactivity with ectromelia virus and vaccinia virus.Conclusions:An RAA-CRISPR/Cas12a-based nucleic acid assay for monkeypox virus was established, which would provide a powerful tool for efficient, rapid and specific detection of monkeypox virus.

Objective:To evaluate the immunogenicity of a novel influenza virus mRNA vaccine based on conserved antigens delivered by lipopolyplex (LPP) platform in a mouse model.Methods:Four copies of genes coding for extracellular domain of matrix 2 protein (M2e) and nucleoprotein (NP) of influenza A virus were synthetized after codon optimization. The fusion antigens were transcribed in vitro and delivered by LPP platform, named as LPP-4M2eNP. Expression of M2e and NP in eukaryotic cells was detected by immunofluorescence assay (IFA). BALB/c mice were inoculated intramuscularly twice with 10 μg or 30 μg LPP-4M2eNP vaccine at an interval of four weeks. Antibody response was detected by ELISA and cellular-mediated immunity (CMI) was detected by enzyme-linked immunospot assay (ELISPOT). Results:IFA showed that NP and M2e were expressed correctly in eukaryotic cells. Single dose immunization could induce significant antigen (NP, M2e)-specific CMI and antigen (NP, M2e)-specific antibody response was induced in mice with Th1 type bias after boost immunization. Moreover, NP-specific CMI was increased significantly after the second immunization, while no significant change in M2e-specific CMI was observed.Conclusions:Stronger CMI was triggered in mice by single dose of LPP-4M2eNP vaccine. Furthermore, robust humoral and cellular immune responses were induced after boost immunization. This study suggested that LPP-4M2eNP vaccine, which based on conserved antigen of influenza A and delivered by LPP platform, had great potential for development and application.

Objective:To evaluate the in vitro cross-neutralization of serum antibodies in human and mice immunized with inactivated SARS-CoV-2 vaccine against Delta and Beta variants. Methods:Human serum samples after a second and a third dose of inactivated SARS-CoV-2 vaccine and mouse serum samples after a two-dose vaccination were collected. The neutralizing antibodies in the samples against SARS-CoV-2 strains of prototype, Delta and Beta variants were detected using micro-neutralization assay in biosafety level Ⅲ laboratory. The seroconversion rates and geometric mean titers (GMTs) of antibodies were calculated.Results:The seroconversion rates of antibodies in human serum samples against different SARS-CoV-2 strains were all above 95%. After two-dose vaccination, the GMTs of neutralizing antibodies against the prototype, Delta and Beta strains were 109, 41 and 15, respectively. The GMTs decreased by 2.7 folds and 7.3 folds for the Delta and Beta variants as compared with the prototype strain. After the booster vaccination, the GMTs of neutralizing antibodies against the prototype, Delta and Beta strains were 446, 190 and 86, respectively. The GMTs of neutralizing antibodies against Delta and Beta variants decreased by 2.3 folds and 5.2 folds as compared with that against the prototype strain. The seroconversion rates of antibodies against different SARS-CoV-2 strains in mouse serum samples were all 100%. The GMTs of neutralizing antibodies against the prototype, Delta and Beta strains were 2 037, 862 and 408, respectively. The GMTs decreased by 2.4 folds and 5.0 folds for the Delta and Beta variants.Conclusions:Inactivated SARS-CoV-2 vaccine could induce a certain level of neutralizing antibodies against Delta and Beta variants in both human and mouse models. Moreover, a third dose of vaccine induced higher levels of neutralizing antibodies against Delta and Beta variants in human. This study provided valuable data for the clinical application and protective evaluation of the inactivated SARS-CoV-2 vaccine.

Objective:To evaluate the performance of two commercial EIA kits for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibodies.Methods:Two commercial SARS-CoV-2 neutralizing antibody ELISA test kits (A and B) were used to detect serum panel consists of the following sera: 44 collected before vaccination, 120 collected one month after vaccination and 64 collected six months after recovery from convalescent patients of COVID-19. In the meantime, the above samples were also taken for live virus micro-neutralization test (micro-NT) indicated as the 50% neutralization antibody titer (NT 50). The consistency of qualitative and quantitative results between the two commercial kits and live virus neutralization test was analyzed. Results:Taking the micro-NT results as the standard, the positive coincidence rates of A and B kits were 97.40% and 100.00%, respectively; the negative coincidence rates were 97.30% and 95.95%, respectively; the Youden indices were 0.95 and 0.96, respectively. Furthermore, quantitative analysis indicated that the correlation coefficients between A and B kits and micro-NT results were 0.24 ( P<0.05) and 0.52 ( P<0.000 1) for samples collected after vaccination, respectively; while the correlation coefficients were 0.81 ( P<0.000 1) and 0.89 ( P<0.000 1) for convalescent serum samples, respectively. Conclusions:The results obtained by the two commercial neutralizing antibody detection kits were in good agreement with the qualitative results of micro-NT. The neutralizing antibody titers in convalescent serum samples detected by the two kits showed a stronger correlation with the micro-NT results.