Antibodies, Neutralizing/immunology* ; Antibodies, Viral/immunology* ; COVID-19/virology* ; COVID-19 Vaccines/immunology* ; Humans ; SARS-CoV-2/pathogenicity* ; Spike Glycoprotein, Coronavirus/immunology* ; Vaccines, Inactivated/immunology*

OBJECTIVETo express the nuclear capsid protein (N protein) and the spike protein (S protein) of HCoV-HKU1, and to develop the corresponding serum assay for antibody detection.

METHODSThe N protein of HCoV-HKU1 was expressed in E. Coli, anti-N antibody assay was established using Western Blotting with turn-based membrane. HCoV-HKU1 S protein was constructed in the eukaryotic expression plasmids, and confirmed by Western Blotting, S antibody assay was established using indirect immunofluorescence assay (IFA). We analyzed anti-S and anti-N antibody among 100 normal adult serum.

RESULTSExpression of S and N protein were confirmed; 100 normal adult serum were analyzed using the established serological detection assay, in which HCoV-HKU1 S antibody positive rate was 47%, N antibody positive rate was 48%, Both S and N antibodies positive were 21%, Both S and N antibodies negative were 22%. Co-detection S and N antibody was achieved 74% positive rate.

CONCLUSIONThe methods we established here could be used for serological analysis of HCoV-HKU1. Either detection of HCoV-HKU1 S or N antibodies achieved good results. Higher positive detection rate of anti-S or anti-N antibody was found in the normal adults.

Antibodies, Viral ; blood ; immunology ; Capsid Proteins ; genetics ; immunology ; Cell Line ; Coronavirus ; genetics ; immunology ; isolation & purification ; physiology ; Coronavirus Infections ; blood ; diagnosis ; immunology ; virology ; Humans ; Membrane Glycoproteins ; genetics ; immunology ; Serologic Tests ; methods ; Spike Glycoprotein, Coronavirus ; Viral Envelope Proteins ; genetics ; immunology

Humans ; Membrane Glycoproteins ; immunology ; SARS Virus ; immunology ; Severe Acute Respiratory Syndrome ; prevention & control ; Spike Glycoprotein, Coronavirus ; Vaccines, DNA ; immunology ; Vaccines, Inactivated ; immunology ; Vaccines, Synthetic ; immunology ; Viral Envelope Proteins ; immunology ; Viral Vaccines ; immunology ; Virion ; immunology

The entire S1 protein gene of five infectious bronchitis (IB) vaccine strains (JAAS, IBN, Jilin, J9, H120) used in China were compared with that of the IB field isolate CK/CH/LDL/97 I present in China. The nucleotide and deduced amino acid similarities between the five IB vaccine strains and the field strain, CK/CH/LDL/97 I, were not more than 76.4% and 78.7%, respectively. Phylogenetic analysis based on the S1 gene showed that the vaccine strains and the field strain belonged to different clusters and had larger evolutionary distances, indicating that they were of different genotypes. The five vaccine strains were used for protection test against challenge of the field isolate CK/CH/LDL/97 I. The chickens inoculated with five vaccine strains showed morbidity as high as 30%-100% after challenged with the CK/CH/ LDL/97 I strain. The organ samples at 5 days post challenge showed that the viral detection rates were 50%-90% and 10%-30% for trachea and kidney, respectively. The live attenuated vaccines only provided partial protection to the vaccinated chickens against heterologous IBV infection, CK/CH/LDL/97 I.
Animals ; Antibodies, Viral ; blood ; Chickens ; virology ; Coronavirus Infections ; prevention & control ; veterinary ; Infectious bronchitis virus ; classification ; genetics ; immunology ; isolation & purification ; Membrane Glycoproteins ; genetics ; Phylogeny ; Poultry Diseases ; prevention & control ; Spike Glycoprotein, Coronavirus ; Vaccines, Attenuated ; immunology ; Viral Envelope Proteins ; genetics ; Viral Vaccines ; immunology

The aim of this study is to construct a SARS-CoV S protein-specific phage displayed antigen library for the epitope characterization of anti-S monoclonal antibodies (mAbs). First, the full-length gene of SARS-S protein was PCR amplified, purified and then digested with DNase I to obtain DNA fragments in the size range of 50-500 bp. The resulting fragments were blunt-end ligated to the modified phage display vector pComb3XSS. The reactions were electrotransformed into XL1-Blue and infected with VCSM13 helper phage. The SARS-CoV S protein-specific phage displayed antigen library was biopanned and screened against two anti-S mAbs, S-M1 and S-M2. The results showed that we successfully constructed the phage displayed antigen library with a size of 5.7 x 10(6). After three-rounds of biopanning, 14 positive phage clones for S-M1 and 15 for S-M2 were respectively identified. Sequence analyses revealed the possible epitopes of two mAbs. Therefore, the S protein-specific phage displayed antigen library provides a crucial platform for the epitope characterization of anti-S antibodies and it is highly valuable for development of SARS vaccines and diagnostics.
Antibodies, Viral ; immunology ; Bacteriophages ; genetics ; metabolism ; Epitopes ; genetics ; immunology ; Humans ; Membrane Glycoproteins ; genetics ; immunology ; Peptide Library ; SARS Virus ; genetics ; immunology ; Severe Acute Respiratory Syndrome ; immunology ; virology ; Spike Glycoprotein, Coronavirus ; Viral Envelope Proteins ; genetics ; immunology

We wished to ascertain the prevalence as well as the genetic and antigenic variation of infectious bronchitis viruses (IBVs) circulating in the Guangxi Province of China in recent years. The S1 gene of 15 IBV field isolates during 2012-2013 underwent analyses in terms of the similarity of amino-acid sequences, creation of phylogenetic trees, recombination, and serologic identification. Similarities in amino-acid sequences among the 15 isolates of the S1 gene were 54.3%-99.6%, and 43.3%-99.3% among 15 isolates and reference strains. Compared with the vaccine strain H120, except for GX-YL130025, the other 14 isolates showed a lower similarity of amino-acid sequences of the S1 gene (65.1-81.4%). Phylogenetic analyses of the S1 gene suggested that 15 IBV isolates were classified into eight genotypes, with the predominant genotype being new-type II. Recombination analyses demonstrated that the S1 gene of the GX-NN130048 isolate originated from recombination events between vaccine strain 4/91 and a LX4-like isolate. Serotyping results suggested that seven serotypes prevailed during 2012-2013 in Guangxi Province, and that only one isolate was consistent with the vaccine strain H120 in serotype (which has been used widely in recent years). The serotype of recombinant isolate GX-NN130048 was different from those of its parent strains. These results suggested that not only the genotype, but also the serotype of IBV field isolates in Guangxi Province had distinct variations, and that increasing numbers of genotypes and serotypes are in circulation. We showed that recombination events can lead to the emergence of new serotypes. Our study provides new evidence for understanding of the molecular mechanisms of IBV variations, and the development of new vaccines against IBVs.
Animals ; Antibodies, Viral ; blood ; Chickens ; China ; Coronavirus Infections ; blood ; veterinary ; virology ; Genetic Variation ; Genotype ; Infectious bronchitis virus ; classification ; genetics ; immunology ; isolation & purification ; Molecular Sequence Data ; Phylogeny ; Poultry Diseases ; blood ; virology ; Sequence Homology, Amino Acid ; Spike Glycoprotein, Coronavirus ; chemistry ; genetics ; immunology

Animals ; Antibodies, Viral ; blood ; Cytokines ; blood ; Female ; Immunoglobulin G ; blood ; classification ; Membrane Glycoproteins ; immunology ; Mice ; Mice, Inbred BALB C ; Recombinant Proteins ; immunology ; Severe Acute Respiratory Syndrome ; immunology ; Spike Glycoprotein, Coronavirus ; T-Lymphocyte Subsets ; immunology ; Viral Envelope Proteins ; immunology

To identify the epitope of SARS-CoV spike protein specific neutralizing monoclonal antibody (MAb) 2C5. The antibody was used as target and three rounds of bio-panning were conducted with phage-display peptide library. After the third panning, 20 phage-plague clones were randomly picked and analyzed for the binding ability with the MAb 2C5 by ELISA. The display sequence analysis demonstrated that among the twenty phage clones, eight clones displayed the same seven-peptide TPEQQFT. All these eight phage-clones showed strongest binding activity with 2C5 in phage ELISA analysis. Furthermore, phages displaying peptide TPEQQFT could specifically inhibit the binding of MAb 2C5 with SARS-CoV spike protein. The results demonstrated that TPEQQFT is a mimic epitope peptide containing neutralizing MAb 2C5. This study may provide information for further structural and functional analysis of spike protein and development vaccine for severe acute respiratory syndrome.
Amino Acid Sequence ; Antibodies, Monoclonal ; immunology ; Enzyme-Linked Immunosorbent Assay ; Epitopes ; Membrane Glycoproteins ; chemistry ; immunology ; Molecular Sequence Data ; Peptide Library ; SARS Virus ; immunology ; Spike Glycoprotein, Coronavirus ; Viral Envelope Proteins ; chemistry ; immunology

The severe acute respiratory syndrome-associated coronavirus (SARS-CoV) spike protein (S) is a major target for neutralizing antibody. To develop and apply a safe neutralization assay for SARS-CoV, lentiviral SARS-CoV S pseudotypes had been constructed based on a three plasmid system, which contained pVRC8304 (harboring codon optimized full-length SARS-CoV S protein), pCMV delta 8. 2 (HIV-1 gag/pol construct) and pHR'CMV EGFP (the green fluorescent protein reporter construct). The pseudo-typed lentiviral particles were used to develop an in vitro microneutralization assay that was both sensitive and specific for SARS-CoV neutralizing antibody. We used this assay to determine the titers of the neutralizing antibodies (Nabs) in serum samples from mice immunized with various rVVs expressing different S fragments of SARS-CoV. The serum antibodies derived from S and various segments of S1 region neutralized SARS-CoV in vitro. No cross-neutralization occurred with the goat antiserum prepared with inactivated HCoV-OC43 or HCoV-229E. Neutralization titers measured by this assay were highly parallel with those measured by the assay using live SARS-CoV. Because the pseudotype assay does not require handling live SARS virus, it is a useful tool to determine serum neutralizing titers during natural infection and the preclinical evaluation of candidate vaccines.
Animals ; Antibodies, Viral ; blood ; Blotting, Western ; Lentivirus ; genetics ; Membrane Glycoproteins ; immunology ; Mice ; Neutralization Tests ; methods ; Plasmids ; Recombinant Proteins ; immunology ; Research Design ; SARS Virus ; immunology ; Spike Glycoprotein, Coronavirus ; Viral Envelope Proteins ; immunology

Middle East respiratory syndrome coronavirus (MERS-CoV) was identified as a novel human coronavirus and posed great threat to public health world wide,which calls for the development of effective and safe vaccine urgently. In the study, peptide epitopes tagrgeting spike antigen were predicted based on bioinformatics methods. Nine polypeptides with high scores were synthesized and linked to keyhole limpet hemocyanin (KLH). Female BALB/C mice were immunized with individual polypeptide-KLH, and the total IgG was detected by ELISA as well as the cellular mediated immunity (CMI) was analyzed using ELIs-pot assay. The results showed that an individual peptide of YVDVGPDSVKSACIEVDIQQTFFDKTWPRPIDVSKADGI could induce the highest level of total IgG as well as CMI (high frequency of IFN-γ secretion) against MERS-CoV antigen in mice. Our study identified a promising peptide vaccine candidate against MERS-CoV and provided an experimental support for bioinformatics-based design of peptide vaccine.
Animals ; Antibodies, Viral ; immunology ; Computational Biology ; Coronavirus Infections ; immunology ; prevention & control ; virology ; Female ; Humans ; Immunization ; Mice ; Mice, Inbred BALB C ; Middle East Respiratory Syndrome Coronavirus ; genetics ; immunology ; Peptides ; administration & dosage ; genetics ; immunology ; Spike Glycoprotein, Coronavirus ; administration & dosage ; genetics ; immunology ; Viral Vaccines ; administration & dosage ; genetics ; immunology