This study investigates the feasibility of the VP8*protein as a subunit vaccine target for porcine rotavirus A(PoRVA),a major causative agent of diarrhea in piglets.The VP8* genes of PoRVA P[13]and P[23]genotype strains were amplified by RT-PCR.These genes were then liga-ted into the pET-28a(+)vector,yielding recombinant plasmids pET-28a-XJWF1-VP8*-P[23]and pET-28a-ShXYW13-VP8*-P[13].These plasmids were subsequently transformed into BL21(DE3)competent cells.The VP8*protein,induced by IPTG,was purified using affinity chroma-tography,and its expression and purification were verified by SDS-PAGE and Western blot.The purified VP8* protein was used to immunize mice,and serum samples were collected after three immunizations.Cross-neutralization assays were conducted to evaluate the ability of the VP8*protein immune serum to neutralize different genotype strains.The results demonstrated the ex-pression of soluble VP8*protein,with SDS-PAGE and Western blot analyses showing that the purified VP8*protein existed in both monomeric(27 kDa)and homodimeric(54 kDa)forms.ELISA results indicated that high levels of antibodies were produced in mice immunized with VP 8*-P[13]and VP8*-P[23]after three immunizations.Serum cross-neutralization assays revealed that the neutralizing titers of PoRVA VP8*-P[13]and VP8*-P[23]immune sera against homol-ogous genotype strains ranged from 1∶4 800 to 1∶19 200,significantly higher than those against heterologous genotype strains(1∶1 200).This suggests that the VP8*protein of different geno-type strains exhibits both antigenic conservation and distinct variability.The data obtained in this study provide a solid foundation for further exploration of the antigenic structure of the PoRVA VP8* protein and the development of novel subunit vaccines.

The rabies virus(RABV)that causes rabies mainly attacks the peripheral and central nervous systems.In the later stages of infection,it is scattered in the salivary glands and transmit-ted to other susceptible animals through infectious saliva.To study dispersion of the RABV in the three pairs of salivary gland tissues,the street strain PB4 of the RABV was inoculated into 21-day-old female mice through the hind limb muscles.During the moribund stage of the mice,the sublin-gual gland,submandibular gland and parotid gland were collected,respectively.The TCID50 titer of RABV in the three kinds of glands of the mice and the copy number of the RABV N gene were de-tected,and RABV in different salivary glands was observed by immunofluorescence.The results showed that PB4 was dispersed in all three kinds of salivary glands of the mice,with the largest a-mounts in the parotid gland,followed by the submandibular gland,and the lowest amount in the sublingual gland.Three-month-old dogs were inoculated with PB4 through the cranial cavity,and saliva were collected every 12 h after inoculation.The saliva samples were detected by TCID50 and RT-qPCR.And during the moribund stage of the dogs when the disease occurred,the three pairs of salivary glands were collected.Through the determination of the TCID50 titer,RT-qPCR and immu-nofluorescence detection,it was demonstrated that among the three different salivary glands of the dogs,the largest amount of PB4 was found in the parotid gland and the lowest in the sublingual gland.Our results in mice and dogs clearly proved that the parotid gland was consistently found to exhibit the highest content of street RABV among the three major salivary glands,which could en-rich experimental data for analyzing the dispersion of RABV in the salivary glands and interpreta-tion of the intermittent secretion of saliva in clinically rabid dogs.

This study aims to inquire about the fluctuations of ubiquitin-specific protease 47 on neu-roblastoma cells(Neuro-2a,N2a)infected by rabies virus(RABV).USP47 expression levels were detected after RABV infection in N2a cells through RT-qPCR,protein immunoblotting,and virus titer determination.The levels of RABV nucleoprotein and phosphoprotein gene and protein,and RABV titers in supernatants were analyzed during overexpression and knockdown of USP47.The results showed that RABV infection increased USP47 gene level in N2a cells.When overexpression of USP47,the levels of RABV N and P were increased,and the virus titers were also improved.Mo-reover,the level of interleukin-6(IL-6)genes decreased.Knocking down USP47 expression reduced levels of RABV N and P genes and proteins,lowered the virus titer,and elevated the IL-6 gene lev-el.The results suggest that USP47 promotes RABV infection and suppresses IL-6 expression.This finding lays the foundation for further investigation into the molecular mechanisms by which USP47 regulates RABV infection.

To establish a highly specific,sensitive,and efficient method for detecting antibodies a-gainst the Erns protein of classical swine fever virus(CSFV),and to distinguish CSFV vaccine strains from wild strains infections in combination with the E2 subunit vaccine.The purified Erns protein of the CSFV expressed by baculovirus was conjugated to carboxylated magnetic beads as a solid-phase carrier and horseradish peroxidase(HRP),separately.A double-antigen sandwich chemiluminescent enzyme immunoassay(CLEIA)was developed by optimizing various reaction parameters using a fully automated chemiluminescence analyzer.This method was then applied to quantitatively detect Erns protein antibodies in sera from pigs infected with prevalent strains and those immunized with the CSFV E2 subunit vaccine and challenged with field strains.The results showed that the optimal conditions for coupling protein-to-magnetic bead were as follows:coupling buffer pH of 8.0,a protein coupling amount of 2.5 mg/g,blocking solution of 10％BSA,serum sample volume of 20 μL.The optimal dilution of enzyme-labeled antigen was at 1:500 with a one-step reaction time of 15 minutes.The cutoff value of the established CLEIA method for detecting CSFV Erns protein antibodies was 5.83 U/mL and a diagnostic sensitivity of 1:128.No cross-reac-tivity was observed with positive sera against African swine fever virus,pseudorabies virus,porcine circovirus type 2,porcine epidemic diarrhea virus,porcine reproductive and respiratory syndrome virus,or porcine gastroenteritis virus.Additionally,the method yielded negative results with sera from pigs immunized with the E2 subunit vaccine.In repeatability tests,the intra-assay coefficient of variation(CV)ranged from 0.77％to 11.56％,and the inter-assay CV ranged from 10.30％to 14.55％,both below 15％.The positive and negative concordance rates with a commercial CSFV Erns protein antibody detection kit were 95.24％and 92.71％,separately,with an overall concord-ance rate of 93.23％.The double-antigen sandwich chemiluminescence method established in this study exhibits high sensitivity,excellent repeatability,and suitability for automated detection,making it applicable for serological differentiation between CSFV E2 subunit vaccination and infec-tion with prevalent strains.

This study investigates the feasibility of the VP8*protein as a subunit vaccine target for porcine rotavirus A(PoRVA),a major causative agent of diarrhea in piglets.The VP8* genes of PoRVA P[13]and P[23]genotype strains were amplified by RT-PCR.These genes were then liga-ted into the pET-28a(+)vector,yielding recombinant plasmids pET-28a-XJWF1-VP8*-P[23]and pET-28a-ShXYW13-VP8*-P[13].These plasmids were subsequently transformed into BL21(DE3)competent cells.The VP8*protein,induced by IPTG,was purified using affinity chroma-tography,and its expression and purification were verified by SDS-PAGE and Western blot.The purified VP8* protein was used to immunize mice,and serum samples were collected after three immunizations.Cross-neutralization assays were conducted to evaluate the ability of the VP8*protein immune serum to neutralize different genotype strains.The results demonstrated the ex-pression of soluble VP8*protein,with SDS-PAGE and Western blot analyses showing that the purified VP8*protein existed in both monomeric(27 kDa)and homodimeric(54 kDa)forms.ELISA results indicated that high levels of antibodies were produced in mice immunized with VP 8*-P[13]and VP8*-P[23]after three immunizations.Serum cross-neutralization assays revealed that the neutralizing titers of PoRVA VP8*-P[13]and VP8*-P[23]immune sera against homol-ogous genotype strains ranged from 1∶4 800 to 1∶19 200,significantly higher than those against heterologous genotype strains(1∶1 200).This suggests that the VP8*protein of different geno-type strains exhibits both antigenic conservation and distinct variability.The data obtained in this study provide a solid foundation for further exploration of the antigenic structure of the PoRVA VP8* protein and the development of novel subunit vaccines.

The rabies virus(RABV)that causes rabies mainly attacks the peripheral and central nervous systems.In the later stages of infection,it is scattered in the salivary glands and transmit-ted to other susceptible animals through infectious saliva.To study dispersion of the RABV in the three pairs of salivary gland tissues,the street strain PB4 of the RABV was inoculated into 21-day-old female mice through the hind limb muscles.During the moribund stage of the mice,the sublin-gual gland,submandibular gland and parotid gland were collected,respectively.The TCID50 titer of RABV in the three kinds of glands of the mice and the copy number of the RABV N gene were de-tected,and RABV in different salivary glands was observed by immunofluorescence.The results showed that PB4 was dispersed in all three kinds of salivary glands of the mice,with the largest a-mounts in the parotid gland,followed by the submandibular gland,and the lowest amount in the sublingual gland.Three-month-old dogs were inoculated with PB4 through the cranial cavity,and saliva were collected every 12 h after inoculation.The saliva samples were detected by TCID50 and RT-qPCR.And during the moribund stage of the dogs when the disease occurred,the three pairs of salivary glands were collected.Through the determination of the TCID50 titer,RT-qPCR and immu-nofluorescence detection,it was demonstrated that among the three different salivary glands of the dogs,the largest amount of PB4 was found in the parotid gland and the lowest in the sublingual gland.Our results in mice and dogs clearly proved that the parotid gland was consistently found to exhibit the highest content of street RABV among the three major salivary glands,which could en-rich experimental data for analyzing the dispersion of RABV in the salivary glands and interpreta-tion of the intermittent secretion of saliva in clinically rabid dogs.

To establish a highly specific,sensitive,and efficient method for detecting antibodies a-gainst the Erns protein of classical swine fever virus(CSFV),and to distinguish CSFV vaccine strains from wild strains infections in combination with the E2 subunit vaccine.The purified Erns protein of the CSFV expressed by baculovirus was conjugated to carboxylated magnetic beads as a solid-phase carrier and horseradish peroxidase(HRP),separately.A double-antigen sandwich chemiluminescent enzyme immunoassay(CLEIA)was developed by optimizing various reaction parameters using a fully automated chemiluminescence analyzer.This method was then applied to quantitatively detect Erns protein antibodies in sera from pigs infected with prevalent strains and those immunized with the CSFV E2 subunit vaccine and challenged with field strains.The results showed that the optimal conditions for coupling protein-to-magnetic bead were as follows:coupling buffer pH of 8.0,a protein coupling amount of 2.5 mg/g,blocking solution of 10％BSA,serum sample volume of 20 μL.The optimal dilution of enzyme-labeled antigen was at 1:500 with a one-step reaction time of 15 minutes.The cutoff value of the established CLEIA method for detecting CSFV Erns protein antibodies was 5.83 U/mL and a diagnostic sensitivity of 1:128.No cross-reac-tivity was observed with positive sera against African swine fever virus,pseudorabies virus,porcine circovirus type 2,porcine epidemic diarrhea virus,porcine reproductive and respiratory syndrome virus,or porcine gastroenteritis virus.Additionally,the method yielded negative results with sera from pigs immunized with the E2 subunit vaccine.In repeatability tests,the intra-assay coefficient of variation(CV)ranged from 0.77％to 11.56％,and the inter-assay CV ranged from 10.30％to 14.55％,both below 15％.The positive and negative concordance rates with a commercial CSFV Erns protein antibody detection kit were 95.24％and 92.71％,separately,with an overall concord-ance rate of 93.23％.The double-antigen sandwich chemiluminescence method established in this study exhibits high sensitivity,excellent repeatability,and suitability for automated detection,making it applicable for serological differentiation between CSFV E2 subunit vaccination and infec-tion with prevalent strains.

This study aims to inquire about the fluctuations of ubiquitin-specific protease 47 on neu-roblastoma cells(Neuro-2a,N2a)infected by rabies virus(RABV).USP47 expression levels were detected after RABV infection in N2a cells through RT-qPCR,protein immunoblotting,and virus titer determination.The levels of RABV nucleoprotein and phosphoprotein gene and protein,and RABV titers in supernatants were analyzed during overexpression and knockdown of USP47.The results showed that RABV infection increased USP47 gene level in N2a cells.When overexpression of USP47,the levels of RABV N and P were increased,and the virus titers were also improved.Mo-reover,the level of interleukin-6(IL-6)genes decreased.Knocking down USP47 expression reduced levels of RABV N and P genes and proteins,lowered the virus titer,and elevated the IL-6 gene lev-el.The results suggest that USP47 promotes RABV infection and suppresses IL-6 expression.This finding lays the foundation for further investigation into the molecular mechanisms by which USP47 regulates RABV infection.

Rabies is a zoonotic disease that poses a global public health threat.Rabies virus(RABV)is neurotropic and can cause severe neurological disorders and behavioral abnormalities in host,with a fatality rate nearly 100％.In order to identify the key genes for RABV affecting neuronal cell function,we established and analyzed the mRNA expression profile of Neuro-2a(N2a)cell in-fected with challenge virus standard(CVS)-11 by RNA sequencing(RNA-seq).Biological func-tions of differentially expressed genes(DEGs)were determined by GO and KEGG enrichment a-nalysis.The results showed that there were 415 differentially expressed genes in N2a infected with CVS-11 strain,of which 89 were up-regulated and 326 were down-regulated.These genes were re-lated to a variety of biological processes,such as axon guidance pathway,cholesterol metabolism pathway,nitrogen metabolism pathway,and glycosphingolipid biosynthesis pathway,many of them have been shown to be closely associated with RABV infection.A total of 12 DEGs related to axon conduction,antigen processing and presentation pathways were selected and detected by real-time PCR,and their expression trends were consistent with the RNA-seq results.The genomic tran-scriptomic data on N2a cell under RABV infection will provide new clues for probing the mecha-nisms of RABV infection and transmission in the nervous system in the future.

Objective To investigate the epidemiological characteristics of Mycoplasma pneumoniae(MP)infection in children in Nanjing Integrated Traditional Chinese and Western Medicine Hospital before and after the COVID-19 outbreak,and provide an experi-mental basis for the prevention and treatment of MP infection.Methods The clinical data of 17 976 children visited Nanjing Integrated Traditional Chinese and Western Medicine Hospital from January 2019 to November 2023 due to respiratory tract infections were retro-spectively analyzed.The levels of serum specific MP-IgM in the children were detected by the direct luminescence immunoassay,and the detection rates of MP-IgM in different genders,seasons,and ages before and after the COVID-19 epidemic were analyzed using the chi square test to explore the epidemiological characteristics of MP infection.Results The total detection rate of serum MP-IgM in 17 976 children with respiratory tract infections was 28.45%(5 114/17 976).Among them,the total detection rate of serum MP-IgM in female children(31.69%,2 672/8 432)was significantly higher than that in male children(25.59%,2 442/9 544,χ2=81.89,P＜0.001).The detection rate of serum MP-IgM was highest in 2019(34.35%,1 415/4 119),followed by in 2023(30.11%,2 409/8 001)and in 2020-2022(22.03%,1 290/5 856),with statistically significant difference(χ2=19.95,P＜0.001).The detection rate of serum MP-IgM was highest in autumn(33.16%,1 683/5 075),followed by in summer(28.61%,1 053/3 681),winter(27.65%,1 826/6 604),and spring(21.10%,552/2 616),with statistically significant difference(χ2=126.90,P＜0.001).Among different age groups,the detection rate of serum MP-IgM was highest in the age group of 7-9 years old(35.83%,1 190/3 321),fol-lowed by 4-6 years old(28.06%,1 882/6 707),1-3 years old(26.55%,1 493/5 623),10-18 years old(23.64%,486/2 056),and＜1 year old(23.42%,63/269),with statistically significant difference(χ2=126.11,P＜0.001).Conclusion MP is a common pathogen of respiratory tract infections in children,especially in the age range of 7-9 years old,with female children having a higher in-cidence than male children,and the peak incidence in autumn.The effective prevention and control measures during the COVID-19 ep-idemic have reduced the detection rate of MP-IgM,which may provide certain experimental basis for the control and prevention of MP infection transmission and other respiratory diseases.