Vaccination is the most effective measure for reducing and preventing influenza and related complications. In this study, we analyzed the mutation trend and the antigen dominant site changes of the amino acid sequence of hemagglutinin subunit 1 (HA1) of human influenza A virus (IAV) in the northern hemisphere from 2012 to 2022. According to the HA1 sequences of A/Darwin/6/2021 (H3N2) and A/Wisconsin/588/2019 (H1N1) recommended by the World Health Organization in the 2022 influenza season in northern hemisphere, we employed the mosaic algorithm to design three Mosaic-HA1 antigens through stepwise substitution. Mosaic-HA1 was expressed and purified in 293F cells and then mixed with the alum adjuvant at a volume ratio of 1:1. The mixture was used to immunize BALB/c mice, and the immunogenicity was evaluated. Enzyme-linked immunosorbent assay showed that Mosaic-HA1 induced the production of IgG targeting two types of HA1, the specific IgG titers for binding to H3 protein and H1 protein reached 10⁵ and 10³ respectively. The challenge test showed that Mosaic-HA1 protected mice from H3N2 or H1N1. This study designs the vaccines by recombination of major antigenic sites in different subtypes of IAV, giving new insights into the development of multivalent subunit vaccines against influenza.
Animals ; Influenza A Virus, H1N1 Subtype/genetics* ; Influenza A Virus, H3N2 Subtype/genetics* ; Mice, Inbred BALB C ; Mice ; Influenza Vaccines/genetics* ; Hemagglutinin Glycoproteins, Influenza Virus/genetics* ; Humans ; Antibodies, Viral/blood* ; Antigens, Viral/genetics* ; Immunoglobulin G/immunology* ; Female ; Orthomyxoviridae Infections/prevention & control* ; HEK293 Cells

BACKGROUND: The new emerging avian influenza A H7N9 virus, causing severe human infection with a mortality rate of around 41%. This study aims to provide a novel treatment option for the prevention and control of H7N9. METHODS: H7 hemagglutinin (HA)-specific B cells were isolated from peripheral blood plasma cells of the patients previously infected by H7N9 in Jiangsu Province, China. The human monoclonal antibodies (mAbs) were generated by amplification and cloning of these HA-specific B cells. First, all human mAbs were screened for binding activity by enzyme-linked immunosorbent assay. Then, those mAbs, exhibiting potent affinity to recognize H7 HAs were further evaluated by hemagglutination-inhibiting (HAI) and microneutralization in vitro assays. Finally, the lead mAb candidate was selected and tested against the lethal challenge of the H7N9 virus using murine models. RESULTS: The mAb 6-137 was able to recognize a panel of H7 HAs with high affinity but not HA of other subtypes, including H1N1 and H3N2. The mAb 6-137 can efficiently inhibit the HA activity in the inactivated H7N9 virus and neutralize 100 tissue culture infectious dose 50 (TCID50) of H7N9 virus (influenza A/Nanjing/1/2013) in vitro, with neutralizing activity as low as 78 ng/mL. In addition, the mAb 6-137 protected the mice against the lethal challenge of H7N9 prophylactically and therapeutically. CONCLUSION The mAb 6-137 could be an effective antibody as a prophylactic or therapeutic biological treatment for the H7N9 exposure or infection.
Animals ; Antibodies, Monoclonal/therapeutic use* ; Antibodies, Neutralizing/therapeutic use* ; Antibodies, Viral ; Hemagglutinins ; Humans ; Influenza A Virus, H1N1 Subtype ; Influenza A Virus, H3N2 Subtype ; Influenza A Virus, H7N9 Subtype ; Influenza Vaccines ; Influenza in Birds ; Influenza, Human/prevention & control* ; Mice

The conserved hemagglutinin (HA) stem region of avian influenza virus (AIV) is an important target for designing broad-spectrum vaccines, therapeutic antibodies and diagnostic reagents. Previously, we obtained a monoclonal antibody (mAb) (5D3-1B5) which was reactive with the HA stem epitope (aa 428-452) of H7N9 subtype AIV. To systematically characterize the mAb, we determined the antibody titers, including the HA-binding IgG, hemagglutination-inhibition (HI) and virus neutralizing (VN) titers. In addition, the antigenic epitope recognized by the antibody as well as the sequence and structure of the antibody variable region (VR) were also determined. Moreover, we evaluated the cross-reactivity of the antibody with influenza virus strains of different subtypes. The results showed that the 5D3-1B5 antibody had undetectable HI and VN activities against H7N9 virus, whereas it exhibited strong reactivity with the HA protein. Using the peptide-based enzyme-linked immunosorbent assay and biopanning with a phage-displayed random peptide library, a motif with the core sequence (⁴³¹W-⁴³³Y-⁴³⁷L) in the C-helix domain in the HA stem was identified as the epitope recognized by 5D3-1B5. Moreover, the mAb failed to react with the mutant H7N9 virus which contains mutations in the epitope. The VR of the antibody was sequenced and the complementarity determining regions in the VR of the light and heavy chains were determined. Structural modeling and molecular docking analysis of the VR verified specific binding between the antibody and the C-helix domain of the HA stem. Notably, 5D3-1B5 showed a broad cross-reactivity with influenza virus strains of different subtypes belonging to groups 1 and 2. In conclusion, 5D3-1B5 antibody is a promising candidate in terms of the development of broad-spectrum virus diagnostic reagents and therapeutic antibodies. Our findings also provided new information for understanding the epitope characteristics of the HA protein of H7N9 subtype AIV.
Animals ; Antibodies, Monoclonal ; Antibodies, Viral ; Hemagglutinin Glycoproteins, Influenza Virus/genetics* ; Hemagglutinins ; Influenza A Virus, H7N9 Subtype ; Influenza in Birds ; Molecular Docking Simulation

Influenza B virus is one of the causes for seasonal influenza, which can account for serious illness or even death in some cases. We tested the expression of extracellular domain of hemagglutinin (HA-ecto) of influenza B viruses in mammalian cells, and then determined the immunogenicity of HA-ecto in mice. The gene sequence encoding influenza B virus HA-ecto, foldon sequence, and HIS tag was optimized and inserted into pCAGGS vector. The opening reading frame (ORF) of neuraminidase was also cloned into pCAGGS. The pCAGGS-HA-ecto and pCAGGS-NA were co-transfected into 293T cells using linear polyethylenimine. Cell supernatant after transfection was collected after 96 h, and the secreted trimmeric HA-ecto protein was purified by nickel ion affinity chromatography and size exclusion chromatography. Subsequently, the mice were immunized with HA-ecto protein, and the corresponding antibody titers were detected by ELISA and hemagglutination inhibition (HAI) assays. The results showed that soluble trimeric HA-ecto protein could be obtained using mammalian cell expression system. Moreover, trimeric HA-ecto protein, in combination with the adjuvant, induced high levels of ELISA and HAI antibodies against homogenous and heterologous antigens in mice. Thus, the soluble HA-ecto protein expressed in mammalian cells could be used as a recombinant subunit vaccine candidate for influenza B virus.
Animals ; Hemagglutinin Glycoproteins, Influenza Virus/genetics* ; Hemagglutinins/genetics* ; Influenza B virus/metabolism* ; Influenza Vaccines/genetics* ; Mammals/metabolism* ; Mice ; Mice, Inbred BALB C

The aim of this study was to develop a semi-quantitative immunochromatographic method for rapid detection of Newcastle disease virus (NDV) antibodies by expressing HN protein in rice endosperm bioreactor. The recombinant plasmid pUC57-HN was digested by MlyⅠ and XhoⅠ to retrieve the HN gene, while the intermediate vector pMP3 containing promoter, signal peptide and terminator was digested by NaeⅠ and XhoⅠ. The HN gene and the linearized pMP3 were purified and ligated to form a recombinant plasmid pMP3-HN1. Subsequently, pMP3-HN1 and plant vector pCAMBIA1300 were digested by EcoRⅠ and Hind Ⅲ, and the HN1 gene was cloned into pCAMBIA1300. The recombinant plasmid pCAMBIA1300-HN1 was introduced into Agrobacterium tumefaciens EHA105 by electrotransformation, and the pCAMBIA1300-HN1 was transferred into rice callus by agrobacterium-mediated method. After dark culture, callus screening, differentiation, rooting and transplanting, transgenic rice seeds were obtained 4 months later. PCR identified that the HN gene has been inserted into the rice genome. SDS-PAGE and Western blotting indicated that the HN protein was successfully expressed in the positive rice endosperm. The purity of the HN protein was more than 90% by SP cation exchange chromatography and gel filtration chromatography. According to the national standards for the diagnostic techniques of Newcastle disease HI test (HI≥4log₂, positive antibody reaction), a colloidal gold labeled purified HN protein was used to prepare a semi-quantitative test strip by double-antibody sandwich method for rapid detection of NDV antibody. The results showed that the test strip did not cross-react with positive sera against other viruses, and the sensitivity of the test strip reached 1:102 400 for standard positive sera of Newcastle disease. Testing of a total of 308 clinical sera showed that the compliance rate of the test strip with HI test was 97.08%, and the Kappa value was 0.942. In conclusion, high purity recombinant HN protein was obtained from rice endosperm, and a simple, rapid, highly sensitive and highly specific semi-quantitative immunochromatographic strip was developed. The test strip could be used for immune evaluation of the Newcastle disease vaccine.
Animals ; Antibodies, Viral ; Chickens ; HN Protein/metabolism* ; Newcastle Disease/prevention & control* ; Newcastle disease virus/metabolism* ; Oryza/genetics*

The purpose was to discuss the infection status of human parainfluenza virus type 3 (HPIV-3) in children with acute respiratory tract infection(ARTI) in Qingdao, Shandong province, and to analyze the gene characteristics of HPIV-3 hemagglutinin-neuraminidase protein (HN). This study was a cross-sectional study. A total of 1 674 throat swab samples were collected randomly from children with ARTI, in the three hospitals (Qingdao Women and Children's Hospital, West Coast Branch of Affiliated Hospital of Qingdao University, Laoshan Branch of Affiliated Hospital of Qingdao University) from January 2018 to December 2019. Multiplex real-time fluorescence RT-PCR was performed to screen HPIV-3 positive specimens. For HPIV-3 positive specimens, nested PCR was used to amplify the full-length HN gene of HPIV-3. The HN gene was sequenced and compared with the representative strains of HPIV-3 in GenBank, and the phylogenetic tree was established. As results, this study collected 1 674 samples, in which there were 90 HPIV-3 positive samples showed and the detection rate was 5.37%. Among positive specimens, the number of samples from children under 6 years old was 88, accounting for 97.78%. HPIV-3 positive cases were mainly distributed in spring and summer. The full-length sequences of 44 HPIV-3 HN genes were obtained by nested PCR method. Sequence alignment and evolutionary analysis showed that the HPIV-3HN gene belonged to the C3a and C3b branches of C3 genotype, with 30 strains of subtype C3a and 14 strains of subtype C3b. The nucleotide and amino acid homology of the amplified 44 strains of the HPIV-3 HN gene in Qingdao were 97.0%-100.0% and 98.5%-100.0%, respectively. In conclusion, from 2018 to 2019, the C3a and C3b branches of HPIV-3 C3 genotype were circulating prevalent in Qingdao, Shandong province. HN gene variation rate was low, but showed certain regional characteristics in evolution.
Child ; Child, Preschool ; Cross-Sectional Studies ; Female ; Hemagglutinins ; Humans ; Neuraminidase ; Parainfluenza Virus 3, Human/genetics* ; Phylogeny ; Respiratory Tract Infections/epidemiology* ; Viral Proteins

To evaluate the immunogenicity of HA globular head domain of H5 subtype influenza virus (H5HA), the gene of H5HA was optimized and the recombinant pPICZaA-H5HA expressing vector was constructed and transfected into Pichia pastoris. The expression of the recombinant H5HA was confirmed by SDS-PAGE and Western blotting and the results demonstrated that the recombinant H5HA (37 kDa) was highly expressed in Pichia pastoris with concentration of 0.2 mg/mL in medium. The recombinant H5HA was concentrated and purified using Ni-NTA affinity chromatography. The immunogenicity of H5HA was evaluated by immunizing eight groups of chicken through intranasal or intramuscular injection with different doses of purified H5HA combined with different adjuvants, respectively. The results showed that the recombinant H5HA could induce high level IgG (HI titer was 1:64 and neutralizing antibody titer was 1:218) and the optimal dosage of the recombinant H5HA was 50 μg combined with oil. In addition, intramuscular injection was better than nasal immunization. This study provided a theoretical support for subunit vaccine development.
Animals ; Antibodies, Viral ; Birds ; Hemagglutinin Glycoproteins, Influenza Virus ; Influenza A Virus, H5N1 Subtype ; Influenza Vaccines ; Influenza in Birds ; Pichia ; Vaccination

Newcastle disease virus (NDV) and Salmonella Pullorum have significant damaging effects on the poultry industry, but no previous vaccine can protect poultry effectively. In this study, a recombinant-attenuated S. Pullorum strain secreting the NDV hemagglutinin-neuraminidase (HN) protein, C79-13ΔcrpΔasd (pYA-HN), was constructed by using the suicide plasmid pREasd-mediated bacteria homologous recombination method to form a new bivalent vaccine candidate against Newcastle disease (ND) and S. Pullorum disease (PD). The effect of this vaccine candidate was compared with those of the NDV LaSota and C79-13ΔcrpΔasd (pYA) strains. The serum hemagglutination inhibition antibody titers, serum immunoglobulin G (IgG) antibodies, secretory IgA, and stimulation index in lymphocyte proliferation were increased significantly more (p < 0.01) in chickens inoculated with C79-13ΔcrpΔasd (pYA-HN) than with C79-13ΔcrpΔasd (pYA) but were not significantly increased compared with the chickens immunized with the LaSota live vaccine (p > 0.05). Moreover, the novel strain provides 60% and 80% protective efficacy against the NDV virulent strain F48E9 and the S. Pullorum virulent strain C79-13. In summary, in this study, a recombinant-attenuated S. Pullorum strain secreting NDV HN protein was constructed. The generation of the S. Pullorum C79-13ΔcrpΔasd (pYA-HN) strain provides a foundation for the development of an effective living-vector double vaccine against ND and PD.
Animals ; Antibodies ; Bacteria ; Chickens ; Hemagglutination ; HN Protein ; Homologous Recombination ; Immunoglobulin A, Secretory ; Immunoglobulin G ; Lymphocytes ; Methods ; Newcastle disease virus ; Newcastle Disease ; Plasmids ; Poultry ; Salmonella ; Suicide ; Vaccines

Objective: To understand the molecular characteristics of hemagglutinin (HA) and neuraminidase (NA) as well as the disease risk of influenza virus A H7N9 in Guizhou province. Methods: RNAs were extracted and sequenced from HA and NA genes of H7N9 virus strains obtained from 18 cases of human infection with H7N9 virus and 6 environmental swabs in Guizhou province during 2014-2017. Then the variation and the genetic evolution of the virus were analyzed by using a series of bioinformatics software package. Results: Homology analysis of HA and NA genes revealed that 2 strains detected during 2014-2015 shared 98.8%-99.2% and 99.2% similarities with vaccine strains A/Shanghai/2/2013 and A/Anhui/1/2013 recommended by WHO, respectively. Two strains detected in 2016 and 14 strains detected in 2017 shared 98.2%-99.3% and 97.6%-98.8% similarities with vaccine strain A/Hunan/02650/2016, respectively. Other 6 stains detected in 2017 shared 99.1%-99.4% and 98.9%-99.3% similarities with strain A/Guangdong/17SF003/2016, respectively. Phylogenetic analysis showed that all the strains were directly evolved in the Yangtze River Delta evolution branch, but they were derived from different small branch. PEVPKRKRTAR↓GLF was found in 6 of 24 strains cleavage site sequences of HA protein, indicating the characteristic of highly pathogenic avian influenza virus. Mutations A134V, G186V and Q226L at the receptor binding sites were found in the HA. All the strains had a stalk deletion of 5 amino acid residue "QISNT" in NA protein, and drug resistance mutation R294K occurred in strain A/Guizhou-Danzhai/18980/2017. In addition, potential glycosylation motifs mutations NCS42NCT were found in the NA of 9 of 24 strains. Conclusions: HA and NA genes of avian influenza A (H7N9) virus showed genetic divergence in Guizhou province during 2014-2017. The mutations of key sites might enhance the virulence of the virus, human beings are more susceptible to it. Hence, the risk of infection is increasing.
Animals ; Base Sequence ; Birds ; China/epidemiology* ; Genome, Viral ; Hemagglutinin Glycoproteins, Influenza Virus/immunology* ; Hemagglutinins/genetics* ; Humans ; Influenza A Virus, H7N9 Subtype/isolation & purification* ; Influenza in Birds ; Influenza, Human/virology* ; Neuraminidase/genetics* ; Phylogeny ; RNA, Viral/genetics* ; Sequence Analysis, DNA

To analyze the genetic characterization of epidemic mumps virus strains in Liaoning Province and provide the basis for mumps control. A total of 32 mumps viruses strains were isolated during 2008-2104. The fragment of SH genes and HN genes were amplified by RT-PCR, the PCR products were sequenced and analyzed. Basing on the 316 nucleotides of SH gene, The phylogenetic analyses were processed with the data of WHO mumps reference strains downloaded from GenBank and 32 mumps viruses strains. It showed that the 31 mumps virus strains belong to F genotype except MuVi/Liaoning. CHN/16.11 which was G genotype . Comparing to the A reference strains (Jeryl-Lynn and S-79), F genotype MuV were mutated on 12 amino acids sites and 27 amino acids siteson on HN gene. F genotype MuV added one N-glycosylation site in 464th-466th amino acids. The antigenic sites on HN were mutated on 121th, 123th, 279th, 287th, 336th, 356th and 442th. Maybe, it will influence the MuV antigenic.
Base Sequence ; China ; Genotype ; HN Protein ; chemistry ; genetics ; Humans ; Molecular Sequence Data ; Mumps ; virology ; Mumps virus ; chemistry ; classification ; genetics ; isolation & purification ; Phylogeny ; Sequence Alignment ; Viral Proteins ; chemistry ; genetics