The recent human infection with avian influenza virus revealed that H9N2 influenza virus is the gene donor for H7N9 and H10N8 viruses infecting humans. The crucial role of H9N2 viruses at the animal-human interface mi...The recent human infection with avian influenza virus revealed that H9N2 influenza virus is the gene donor for H7N9 and H10N8 viruses infecting humans. The crucial role of H9N2 viruses at the animal-human interface might be due to the wide host range, adaptation in both poultry and mammalian, and extensive gene reassortment. As the most prevalent subtype of influenza viruses in chickens in China, H9N2 also causes a great economic loss for the poultry industry, even under the long-term vaccination programs. The history, epidemiology, bio- logical characteristics, and molecular determinants of H9N2 influenza virus are reviewed in this paper. The contribution of H9N2 genes, especially RNP genes, to the infection of humans needs to be investigated in the future.展开更多
Background Prompt diagnosis of Mycobacterium tuberculosis （MTB） infection is an essential step in tuberculosis control and elimination. However, it is often difficult to accurately diagnose pediatric tuberculosis ...Background Prompt diagnosis of Mycobacterium tuberculosis （MTB） infection is an essential step in tuberculosis control and elimination. However, it is often difficult to accurately diagnose pediatric tuberculosis （TB）. The tuberculin test （TST） may have a low specificity because of cross-reactivity with antigens present in Mycobacterium bovis bacillus Calmette-Guerin （BCG） and other mycobacteria, especially in China with a predominantly BCG-vaccinated population.Early-secreted antigenic target 6-kDa protein （ESAT-6） and culture filtrate protein 10 （CFP-10）, stand out as suitable antigens that induce an interferon-gamma （IFN-γ） secreting, T-cell-mediated immune response to infection. While,considered the higher costs and complexity of the IFN-γ release assay （TSPOT）, we aimed to evaluate the TSPOT and TST test in the clinical diagnosis of pediatric tuberculosis and to establish a diagnostic process suitable for China.Methods The sensitivity and specificity of the assay were evaluated in total seventy four children with active tuberculosis and fifty one nontuberculous children with other disease, and then the results were compared with TST.Logistic regression models were used to identify variables that were associated with positive results for each assay. The independent variables included sex, age, birth place, vaccination history, close contract with an active TB patient.Results The sensitivity of TSPOT was higher than TST in active TB children with or without BCG vaccination, as well as in children with culture-confirmed TB. But the difference was not significant statistically. Combining results of the TSPOT and TST improved the sensitivity to 94.6%. Agreement of the TST and TSPOT was low （77.0%, k=0.203） in active TB patients. The difference in specificity between TSPOT and TST test was statistically significant （94.1% vs.70.6%, P=0.006）. Specificity of the two tests in patients without prior BCG vaccination history was similar （80.0% vs.60.0%）. The concordance betw展开更多
The human influenza A （H3N2） virus dominated the 2014-2015 winter season in many countries and caused massive morbid- ity and mortality because of its antigenic variation. So far, very little is known about the anti...The human influenza A （H3N2） virus dominated the 2014-2015 winter season in many countries and caused massive morbid- ity and mortality because of its antigenic variation. So far, very little is known about the antigenic patterns of the recent H3N2 virus. By systematically mapping the antigenic relationships of H3N2 strains isolated since 2010, we discovered that two groups with obvious antigenic divergence, named SW13 （A/Switzerland/9715293/2013-1ike strains） and HK14 （A/Hong Kong/5738/2014-1ike strains）, co-circulated during the 2014-2015 winter season. HK14 group co-circulated with SW13 in Europe and the United States during this season, while there were few strains of HK14 in China's Mainland, where SW13 has dominated since 2012. Furthermore, we found that substitutions near the receptor-binding site on hemagglutinin played an im- portant role in the antigenic variation of both the groups. These findings provide a comprehensive understanding of the recent antigenic evolution of H3N2 virus and will aid in the selection of vaccine strains.展开更多
The Coronaviridae family is characterized by a nucleocapsid that is composed of the genome RNA molecule in combination with the nucleoprotein (N protein) within a virion. The most striking physiochemical feature of th...The Coronaviridae family is characterized by a nucleocapsid that is composed of the genome RNA molecule in combination with the nucleoprotein (N protein) within a virion. The most striking physiochemical feature of the N protein of SARS-CoV is that it is a typical basic protein with a high predicted pI and high hydrophilicity, which is consistent with its function of binding to the ribophosphate backbone of the RNA molecule. The predicted high extent of phosphorylation of the N protein on multiple candidate phosphorylation sites demonstrates that it would be related to important functions, such as RNA-binding and localization to the nucleolus of host cells. Subsequent study shows that there is an SR-rich region in the N protein and this region might be involved in the protein-protein interaction. The abundant antigenic sites predicted in the N protein, as well as experimental evidence with synthesized polypeptides, indicate that the N protein is one of the major antigens of the SARS-CoV. Compared with other viral structural proteins, the low variation rate of the N protein with regards to its size suggests its importance to the survival of the virus.展开更多
Helicobacter pylori (H. pylori) infection could be associated with extra-digestive diseases. Here, we report the evidences concerning the decrease in reproductive potential occurring in individuals infected by H. pylo...Helicobacter pylori (H. pylori) infection could be associated with extra-digestive diseases. Here, we report the evidences concerning the decrease in reproductive potential occurring in individuals infected by H. pylori, especially by strains expressing CagA. This infection is more prevalent in individuals with fertility disorders. Infected women have anti-H. pylori antibodies in cervical mucus and follicular fluid that may decrease sperm motility and cross react immunologically with spermatozoa, conceivably hampering the oocyte/sperm fusion. Infection by CagA positive organisms enhances the risk of preeclampsia, which is a main cause of foetus death. These findings are supported by the results of experimental infections of pregnant mice, which may cause reabsorption of a high number of foetuses and alter the balance between Th1 and Th2 cell response. Infected men have decreased sperm motility, viability and numbers of normally shaped sperm and augmented systemic levels of inflammatory cytokines, such as tumor necrosis factor-α, which may damage spermatozoa. In countries where parasitic infestation is endemic, detrimental effects of infection upon spermatozoa may not occur, because the immune response to parasites could determine a switch from a predominant Th1 type to Th2 type lymphocytes, with production of anti-inflammatory cytokines. In conclusion, the evidences gathered until now should be taken into consideration for future studies aiming to explore the possible role of H. pylori infection on human reproduction.展开更多
Influenza virus can rapidly change its antigenicity, via mutation in the hemagglutinin(HA) protein, to evade host immunity. The emergence of the novel human-infecting avian H7N9 virus in China has caused widespread co...Influenza virus can rapidly change its antigenicity, via mutation in the hemagglutinin(HA) protein, to evade host immunity. The emergence of the novel human-infecting avian H7N9 virus in China has caused widespread concern. However, evolution of the antigenicity of this virus is not well understood. Here, we inferred the antigenic epitopes of the HA protein from all H7 viruses, based on the five well-characterized HA epitopes of the human H3N2 virus. By comparing the two major H7 phylogenetic lineages, i.e., the Eurasian lineage and the North American lineage, we found that epitopes A and B are more frequently mutated in the Eurasian lineage, while epitopes B and C are more frequently mutated in the North American lineage. Furthermore, we found that the novel H7N9 virus(derived from the Eurasian lineage) isolated in China in the year 2013, contains six frequently mutated sites on epitopes that include site 135, which is located in the receptor binding domain. This indicates that the novel H7N9 virus that infects human may already have been subjected to gradual immune pressure and receptor-binding variation. Our results not only provide insights into the antigenic evolution of the H7 virus but may also help in the selection of suitable vaccine strains.展开更多
The Influenza A(H1N1)pdm09 virus caused a global pandemic in 2009 and has circulated seasonally ever since.As the continual genetic evolution of hemagglutinin in this virus leads to antigenic drift,rapid identificatio...The Influenza A(H1N1)pdm09 virus caused a global pandemic in 2009 and has circulated seasonally ever since.As the continual genetic evolution of hemagglutinin in this virus leads to antigenic drift,rapid identification of antigenic variants and characterization of the antigenic evolution are needed.In this study,we developed PREDAC-H1pdm,a model to predict antigenic relationships between H1N1pdm viruses and identify antigenic clusters for post-2009 pandemic H1N1 strains.Our model performed well in predicting antigenic variants,which was helpful in influenza surveillance.By mapping the antigenic clusters for H1N1pdm,we found that substitutions on the Sa epitope were common for H1N1pdm,whereas for the former seasonal H1N1,substitutions on the Sb epitope were more common in antigenic evolution.Additionally,the localized epidemic pattern of H1N1pdm was more obvious than that of the former seasonal H1N1,which could make vaccine recommendation more sophisticated.Overall,the antigenic relationship prediction model we developed provides a rapid determination method for identifying antigenic variants,and the further analysis of evolutionary and epidemic characteristics can facilitate vaccine recommendations and influenza surveillance for H1N1pdm.展开更多
Infection and vaccination can provide protective immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the emergence of SARS-CoV-2 variants has persisted, leading to breakthrough infe...Infection and vaccination can provide protective immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the emergence of SARS-CoV-2 variants has persisted, leading to breakthrough infections. Owing to the original antigenic sin (OAS), variant breakthrough infection or vaccination potentially induces a stronger antibody response against the ancestral strain than to subsequent variants, as in the case of influenza. Thus, overcoming OAS is important for the development of future vaccine designs. This review summarizes the recent findings on OAS in the antibody response to SARS-CoV-2 and its variants, with an emphasis on future vaccine designs.展开更多
Mycobacterium tuberculosis 6-kDa early secretory antigenic target （ESAT-6） is a dominant target antigen for cell-mediated immunity in the early phase of tuberculosis. The fms-like tyrosine kinase 3 ligand （FL） tha...Mycobacterium tuberculosis 6-kDa early secretory antigenic target （ESAT-6） is a dominant target antigen for cell-mediated immunity in the early phase of tuberculosis. The fms-like tyrosine kinase 3 ligand （FL） that induces potent immune response has been used as an adjuvant in vaccine development. In this study, a new recombinant plasmid （plRES-epitope-peptides-FL） encoding three T cell epitopes of ESAT-6 and FL was constructed, and the immunogenicity of the DNA vaccine was assessed in C57BL/6 mice immunized with the plasmid DNA vaccine. Additionally, a strategy of intramuscular injection with the DNA vaccine （prime） and intranasal administration of the epitope peptides （boost） was employed to induce higher immune reaction of the mice. The results showed that mice vaccinated with the recombinant plasmid DNA vaccine and boosted with the peptides not only increased the levels of Thl cytokines （IFN-γ and IL-12）, the number of IFN-γ＋ T cells and activities of cytotoxic T lymphocytes as well as IgG, but also enhanced protection against Mycobacterium tuberculosis challenge. In conclusion, these data indicate that the novel recombinant plRES-epitope-peptides-FL plasmid is a useful DNA vaccine for pre- venting Mycobacterium tuberculosis infection.展开更多
To construct cDNA library of nasopharyngeal carcinoma （NPC） and obtain the NPC associated or specific antigens from it, we used a powerful new method to identify the antigens eliciting humoral immune response, which...To construct cDNA library of nasopharyngeal carcinoma （NPC） and obtain the NPC associated or specific antigens from it, we used a powerful new method to identify the antigens eliciting humoral immune response, which is SEREX （serological identification of antigen by recombinant cDNA expression library）. Autologous serum of NPC patient was used to screen the reactive clones in the human NPC tissue cDNA library consisted of 3.64 × 10^6 recombinants. The 23 exact positive clones were subcloned to monoclonality and the size of cDNA inserts was identified by PCR. Then the nucleotide sequence of cDNA inserts was determined, and the sequence alignments were performed with BLAST software on GenBank database. They represented 16 different antigens. A detailed sequence analysis showed that 10 of 16 genes were high homologous to genes known in GenBank, such as RPL31, SI00 A2, MT2A, etc. However, there were also 6 genes with low homology to genes in GenBank. Furthermore, 3 of 6 genes may be novel genes. The associations of these genes to NPC and the roles that they played in the occurrence and development of NPC should be further revealed.展开更多
The genes of the heavy and light chain variable region (VH, VL) of Z12 antibody against hTNF-a were cloned, and according to the translated sequence of amino acids, the spa-tial structures of VH and VL domains were mo...The genes of the heavy and light chain variable region (VH, VL) of Z12 antibody against hTNF-a were cloned, and according to the translated sequence of amino acids, the spa-tial structures of VH and VL domains were modeled by using homology-based modeling method, followed by constructing the whole three-dimensional structure of Fv fragment. The complex model of Fv interacting with hTNF-a was gained with computer-guided molecular docking method, based on which, it was predicted that the epitope recognized by Z12 was from 141 to 146 of hTNF-a. hTNF-a molecule was divided into two fragments of N-terminal region from 1 to 91 and C-terminal region from 92 to 157 with prokaryotic expression. The measured results suggested that the antigenic epitope recognized by Z12 antibody was located in the C-terminal region 92-157 of hTNF-a, proving the predicted result reliable preliminarily. Further experimental results showed that after hTNF- 141-146 residues were deleted, Z12 antibody almost lost the ability to recognize the mutant, suggesting that the amino acid residues from 141 to 146 of hTNF-a were specially recognized by Z12 antibody.展开更多
Immunoproteasome is a variant of proteasome with structural differences in 20S subunits optimizing them for the production of antigenic peptides with higher binding affinity to major histocompatibility complex(MHC)-I ...Immunoproteasome is a variant of proteasome with structural differences in 20S subunits optimizing them for the production of antigenic peptides with higher binding affinity to major histocompatibility complex(MHC)-I molecules.Apart from this primary function in antigen presentation,immunoproteasome is also responsible for the degradation of proteins,both unfolded proteins for the maintenance of protein homeostasis and tumor suppressor proteins contributing to tumor progression.The altered expression of immunoproteasome is frequently observed in cancers;however,its expression levels and effects vary among different cancer types exhibiting antagonistic roles in tumor development.This review focuses on the dichotomous role of immunoproteasome in different cancer types,as well as summarizes the current progression in immunoproteasome activators and inhibitors.Specifically targeting immunoproteasome may be a beneficial therapeutic intervention in cancer treatment and understanding the role of immunoproteasome in cancers will provide a significant therapeutic insight for the prevention and treatment of cancers.展开更多
Different viruses transmit among hosts with different degrees of efficiency. A basic reproductive number(R0) indicates an average number of cases getting infected from a single infected case. R0 can vary widely from a...Different viruses transmit among hosts with different degrees of efficiency. A basic reproductive number(R0) indicates an average number of cases getting infected from a single infected case. R0 can vary widely from a little over 1 to more than 10. Low R0 is usually found among rapidly evolving viruses that are often under a strong positive selection pressure, while high R0 is often found among viruses that are highly stable. The reason for the difference between antigenically diverse viruses with low R0, such as influenza A virus, and antigenically stable viruses with high R0, such as measles virus, is not clear and has been a subject of great interest. Optimization of transmissibility fitness considering intra-host dynamics and inter-host transmissibility was shown to result in strategies for tradeoff between transmissibility and diversity. The nature of transmission, targeting either a na?ve children population or an adult population with partial immunity, has been proposed as a contributing factor for the difference in the strategies used by the two groups of viruses. The R0 determines the levels of threshold heard immunity. Lower R0 requires lowerherd immunity to terminate an outbreak. Therefore, it can be assumed that the outbreak saturation can be reached more readily when the R0 is low. In addition, one may assume that when the outbreak saturation is reached, herd immunity may provide a strong positive selection pressure that could possibly result in an occurrence of escape mutants. Studies of these hypotheses will give us an important insight into viral evolution. This review discusses the above hypotheses as well as some possible mechanistic explanation for the difference in transmission efficiency of展开更多
In this study,a synthesized quadruple antigenic epitope gene region of the classical swine fever virus (CSFV)E2 glycoprotein was expressed in E.coli to a obtain target protein.This target protein was used as a coating...In this study,a synthesized quadruple antigenic epitope gene region of the classical swine fever virus (CSFV)E2 glycoprotein was expressed in E.coli to a obtain target protein.This target protein was used as a coating antigen to establish an indirect ELISA for specifically detecting anti-CSFV antibodies in serum samples from pigs.The P/N cut-off value of this assay was 1.92 by receiver operating characteristic curve(ROC)analysis based on 30 negative sera and 80 positive samples.The test gave 97.5%sensitivity and 96.7%specificity compared with the indirect hemagglutination(IHA)test.The inter-assay and intra-assay coefficients of variation (CVs)for 16 sera were both≤6.8%.No cross-reactivity between the coating antigen and anti-bovine viral diarrhoea virus(BVDV)antibodies was observed.展开更多
Antigenic drift forces us to frequently update influenza vaccines; however, the genetic basis for antigenic variation remains largely unknown. In this study, we used clade 7.2 H5 viruses as models to explore the molec...Antigenic drift forces us to frequently update influenza vaccines; however, the genetic basis for antigenic variation remains largely unknown. In this study, we used clade 7.2 H5 viruses as models to explore the molecular determinants of influenza virus antigenic variation. We generated eight monoclonal antibodies(MAbs) targeted to the hemagglutinin(HA) protein of the index virus A/chicken/Shanxi/2/2006 and found that two representative antigenically drifted clade 7.2 viruses did not react with six of the eight MAbs. The E131 N mutation and insertion of leucine at position 134 in the HA protein of the antigenically drifted strains eliminated the reactivity of the virus with the MAbs. We also found that the amino acid N131 in the H5 HA protein is glycosylated. Our results provide experimental evidence that glycosylation and an amino acid insertion or deletion in HA influence antigenic variation.展开更多
It is a crucial problem in gene engineering whether an exogenous gene could be correctly expressed in cells of transgenic animal or plant, and how the expression products could be detected quantitatively in translatio...It is a crucial problem in gene engineering whether an exogenous gene could be correctly expressed in cells of transgenic animal or plant, and how the expression products could be detected quantitatively in translational level. It is very difficult to analyze some gene expression products, such as isopentenyl transferase (ipt), in transgenic investigation because they are trace in organisms. A convenient method is described to determine trace content gene expression product which is hard to purify. The method includes predicting and synthesizing the antigenic peptide according to the cDNA sequence, coupling the synthetic antigenic peptide with carrier protein, raising specific antibodies against the synthetic antigen, and detecting the gene expression product by ELISA and Western blot.展开更多
Leptospirosis is recognized as the most widespread zoonosis with a global distribution. In this study, the antigenic variation in Leptospira interrogans and Leptospira borgpetersenii isolated from human urine and fiel...Leptospirosis is recognized as the most widespread zoonosis with a global distribution. In this study, the antigenic variation in Leptospira interrogans and Leptospira borgpetersenii isolated from human urine and field rat kidney was preliminarily confirmed by microscopic agglutination test using monoclonal antibodies, and was further subjected to amplification and identification of outer membrane lipoproreins with structural gene variation. Sequence similarity analysis revealed that these protein sequences, namely OmpL1, LipL32 and LipL41, showed no more homologies to outer membrane lipoproteins of non-pathogenic Leptospira and other closely related Spirochetes, but showed a strong identity within L. interrogans, suggesting intra-specific phylogenetic lineages that might be originated from a common pathogenic leptospiral origin. Moreover, the ompL1 gene showed more antigenic variation than lipL32 and lipL41 due to less conservation in secondary structural evolution within closely related species. Phylogenetically, ompL1 and lipL4l of these strains gave a considerable proximity to L. weilii and L. santaro- sai. The ompI,1 gene of L. interrogans clustered distinctly from other pathogenic and non-pathogenic leptospiral species. The diversity of ompL genes has been an- alyzed and it envisaged that sequence-specific variations at antigenic determinant sites would result in slow evolutionary changes along with new serovar origination within closely related species. Thus, a crucial work on effective recombinant vaccine development and engineered antibodies will hopefully meet to solve the therapeutic challenges.展开更多
To investigate the chemical structure of cell wall mannan obtained from pathogenic yeast, Candida tropicalis NBRC 1400 (former antigenic standard strain, IFO 1400). As a result of two-dimensional NMR analysis, it was ...To investigate the chemical structure of cell wall mannan obtained from pathogenic yeast, Candida tropicalis NBRC 1400 (former antigenic standard strain, IFO 1400). As a result of two-dimensional NMR analysis, it was shown that the mannan of this strain is composed of α-1,6-, α-1,3-, α-1,2- and β-1,2-linked mannose residues. In this research, the mannan was subjected to three degradation procedures, acid-treatment, α-mannosidase, and acetolysis under two conditions in order to determine the chemical structure of the antigenic oligomannosyl side chains in this molecule. The 1H-nuclear magnetic resonance spectra of resultant oligosaccharides, pentaose and hexaose, demonstrated the existence of the oligomannosyl side chains corresponding to Manα1-3Manα1-2Manα1-2Manα1-2Man and Manα1-3Manα1-2Manα1-2Manα1-2Manα1-2Man, respectively, which have previously also been found in Candida albicans serotype A strain mannans. These findings indicate that C. tropicalis and C. albicans serotype A have no significant difference in the chemical structure of these cell wall mannans. Therefore, it can be interpreted that it is extremely difficult to distinguish both species by targeting the antigenic group in these mannans.展开更多
文摘The recent human infection with avian influenza virus revealed that H9N2 influenza virus is the gene donor for H7N9 and H10N8 viruses infecting humans. The crucial role of H9N2 viruses at the animal-human interface might be due to the wide host range, adaptation in both poultry and mammalian, and extensive gene reassortment. As the most prevalent subtype of influenza viruses in chickens in China, H9N2 also causes a great economic loss for the poultry industry, even under the long-term vaccination programs. The history, epidemiology, bio- logical characteristics, and molecular determinants of H9N2 influenza virus are reviewed in this paper. The contribution of H9N2 genes, especially RNP genes, to the infection of humans needs to be investigated in the future.
基金This study was supported by the grants from the National Natural Science Foundation of China （No. 30872788） and from the Beijing Municipal Science and Technology Commission （No.Z09050700940903）.
文摘Background Prompt diagnosis of Mycobacterium tuberculosis （MTB） infection is an essential step in tuberculosis control and elimination. However, it is often difficult to accurately diagnose pediatric tuberculosis （TB）. The tuberculin test （TST） may have a low specificity because of cross-reactivity with antigens present in Mycobacterium bovis bacillus Calmette-Guerin （BCG） and other mycobacteria, especially in China with a predominantly BCG-vaccinated population.Early-secreted antigenic target 6-kDa protein （ESAT-6） and culture filtrate protein 10 （CFP-10）, stand out as suitable antigens that induce an interferon-gamma （IFN-γ） secreting, T-cell-mediated immune response to infection. While,considered the higher costs and complexity of the IFN-γ release assay （TSPOT）, we aimed to evaluate the TSPOT and TST test in the clinical diagnosis of pediatric tuberculosis and to establish a diagnostic process suitable for China.Methods The sensitivity and specificity of the assay were evaluated in total seventy four children with active tuberculosis and fifty one nontuberculous children with other disease, and then the results were compared with TST.Logistic regression models were used to identify variables that were associated with positive results for each assay. The independent variables included sex, age, birth place, vaccination history, close contract with an active TB patient.Results The sensitivity of TSPOT was higher than TST in active TB children with or without BCG vaccination, as well as in children with culture-confirmed TB. But the difference was not significant statistically. Combining results of the TSPOT and TST improved the sensitivity to 94.6%. Agreement of the TST and TSPOT was low （77.0%, k=0.203） in active TB patients. The difference in specificity between TSPOT and TST test was statistically significant （94.1% vs.70.6%, P=0.006）. Specificity of the two tests in patients without prior BCG vaccination history was similar （80.0% vs.60.0%）. The concordance betw
基金supported by the National Basic Research Program of China(2015CB910501)the Major National Earmark Project for Infectious Diseases(2014ZX10004002-001)+1 种基金the Key Research Program of the Chinese Academy of Sciences(KJZD-EW-L09-1-2)to Jiang Tai Jiaothe National Natural Science Foundation of China(31470273)to Wu Ai Ping
文摘The human influenza A （H3N2） virus dominated the 2014-2015 winter season in many countries and caused massive morbid- ity and mortality because of its antigenic variation. So far, very little is known about the antigenic patterns of the recent H3N2 virus. By systematically mapping the antigenic relationships of H3N2 strains isolated since 2010, we discovered that two groups with obvious antigenic divergence, named SW13 （A/Switzerland/9715293/2013-1ike strains） and HK14 （A/Hong Kong/5738/2014-1ike strains）, co-circulated during the 2014-2015 winter season. HK14 group co-circulated with SW13 in Europe and the United States during this season, while there were few strains of HK14 in China's Mainland, where SW13 has dominated since 2012. Furthermore, we found that substitutions near the receptor-binding site on hemagglutinin played an im- portant role in the antigenic variation of both the groups. These findings provide a comprehensive understanding of the recent antigenic evolution of H3N2 virus and will aid in the selection of vaccine strains.
文摘The Coronaviridae family is characterized by a nucleocapsid that is composed of the genome RNA molecule in combination with the nucleoprotein (N protein) within a virion. The most striking physiochemical feature of the N protein of SARS-CoV is that it is a typical basic protein with a high predicted pI and high hydrophilicity, which is consistent with its function of binding to the ribophosphate backbone of the RNA molecule. The predicted high extent of phosphorylation of the N protein on multiple candidate phosphorylation sites demonstrates that it would be related to important functions, such as RNA-binding and localization to the nucleolus of host cells. Subsequent study shows that there is an SR-rich region in the N protein and this region might be involved in the protein-protein interaction. The abundant antigenic sites predicted in the N protein, as well as experimental evidence with synthesized polypeptides, indicate that the N protein is one of the major antigens of the SARS-CoV. Compared with other viral structural proteins, the low variation rate of the N protein with regards to its size suggests its importance to the survival of the virus.
文摘Helicobacter pylori (H. pylori) infection could be associated with extra-digestive diseases. Here, we report the evidences concerning the decrease in reproductive potential occurring in individuals infected by H. pylori, especially by strains expressing CagA. This infection is more prevalent in individuals with fertility disorders. Infected women have anti-H. pylori antibodies in cervical mucus and follicular fluid that may decrease sperm motility and cross react immunologically with spermatozoa, conceivably hampering the oocyte/sperm fusion. Infection by CagA positive organisms enhances the risk of preeclampsia, which is a main cause of foetus death. These findings are supported by the results of experimental infections of pregnant mice, which may cause reabsorption of a high number of foetuses and alter the balance between Th1 and Th2 cell response. Infected men have decreased sperm motility, viability and numbers of normally shaped sperm and augmented systemic levels of inflammatory cytokines, such as tumor necrosis factor-α, which may damage spermatozoa. In countries where parasitic infestation is endemic, detrimental effects of infection upon spermatozoa may not occur, because the immune response to parasites could determine a switch from a predominant Th1 type to Th2 type lymphocytes, with production of anti-inflammatory cytokines. In conclusion, the evidences gathered until now should be taken into consideration for future studies aiming to explore the possible role of H. pylori infection on human reproduction.
基金supported by the National Basic Research Program of China(2015CB910501)the Major National Earmark Project for Infectious Diseases(2014ZX10004002-001)+1 种基金the Key Research Program of the Chinese Academy of Sciences(KJZD-EW-L09-1-2)to Jiang Tai Jiaothe National Natural Science Foundation of China(31470273)to Wu Ai Ping
文摘Influenza virus can rapidly change its antigenicity, via mutation in the hemagglutinin(HA) protein, to evade host immunity. The emergence of the novel human-infecting avian H7N9 virus in China has caused widespread concern. However, evolution of the antigenicity of this virus is not well understood. Here, we inferred the antigenic epitopes of the HA protein from all H7 viruses, based on the five well-characterized HA epitopes of the human H3N2 virus. By comparing the two major H7 phylogenetic lineages, i.e., the Eurasian lineage and the North American lineage, we found that epitopes A and B are more frequently mutated in the Eurasian lineage, while epitopes B and C are more frequently mutated in the North American lineage. Furthermore, we found that the novel H7N9 virus(derived from the Eurasian lineage) isolated in China in the year 2013, contains six frequently mutated sites on epitopes that include site 135, which is located in the receptor binding domain. This indicates that the novel H7N9 virus that infects human may already have been subjected to gradual immune pressure and receptor-binding variation. Our results not only provide insights into the antigenic evolution of the H7 virus but may also help in the selection of suitable vaccine strains.
基金funded by the National Natural Science Foundation of China (32070678)the National Key Research and Development Program of China (2021YFC2302001).
文摘The Influenza A(H1N1)pdm09 virus caused a global pandemic in 2009 and has circulated seasonally ever since.As the continual genetic evolution of hemagglutinin in this virus leads to antigenic drift,rapid identification of antigenic variants and characterization of the antigenic evolution are needed.In this study,we developed PREDAC-H1pdm,a model to predict antigenic relationships between H1N1pdm viruses and identify antigenic clusters for post-2009 pandemic H1N1 strains.Our model performed well in predicting antigenic variants,which was helpful in influenza surveillance.By mapping the antigenic clusters for H1N1pdm,we found that substitutions on the Sa epitope were common for H1N1pdm,whereas for the former seasonal H1N1,substitutions on the Sb epitope were more common in antigenic evolution.Additionally,the localized epidemic pattern of H1N1pdm was more obvious than that of the former seasonal H1N1,which could make vaccine recommendation more sophisticated.Overall,the antigenic relationship prediction model we developed provides a rapid determination method for identifying antigenic variants,and the further analysis of evolutionary and epidemic characteristics can facilitate vaccine recommendations and influenza surveillance for H1N1pdm.
基金supported by the National Science Fund for Distinguished Young Scholars(82025022)the National Science Fund for Outstanding Young Scholars(82322040)+6 种基金the National Natural Science Foundation of China(92169204,82302494)the Guangdong Science and Technology Plan Project-Construction of High-level Biosafety Laboratories(2021B1212030010)the Guangdong Basic and Applied Basic Research Foundation(2021B1515020034,2023A1515011883)the Shenzhen Science and Technology Program(RCYX20200714114700046,ZDSYS20210623091810030)the Shenzhen Natural Science Foundation(JCYJ20220530163405012)the Chinese Academy of Medical Sciences Clinical and Translational Medicine Research Project(2022-I2M-C&T-B-113)the Shenzhen High-level Hospital Construction Fund(23250G1002).
文摘Infection and vaccination can provide protective immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the emergence of SARS-CoV-2 variants has persisted, leading to breakthrough infections. Owing to the original antigenic sin (OAS), variant breakthrough infection or vaccination potentially induces a stronger antibody response against the ancestral strain than to subsequent variants, as in the case of influenza. Thus, overcoming OAS is important for the development of future vaccine designs. This review summarizes the recent findings on OAS in the antibody response to SARS-CoV-2 and its variants, with an emphasis on future vaccine designs.
基金supported by the Natural Scientific Fund (09KJA310002DG216D50162011NJMU263 and 11JC005) of China
文摘Mycobacterium tuberculosis 6-kDa early secretory antigenic target （ESAT-6） is a dominant target antigen for cell-mediated immunity in the early phase of tuberculosis. The fms-like tyrosine kinase 3 ligand （FL） that induces potent immune response has been used as an adjuvant in vaccine development. In this study, a new recombinant plasmid （plRES-epitope-peptides-FL） encoding three T cell epitopes of ESAT-6 and FL was constructed, and the immunogenicity of the DNA vaccine was assessed in C57BL/6 mice immunized with the plasmid DNA vaccine. Additionally, a strategy of intramuscular injection with the DNA vaccine （prime） and intranasal administration of the epitope peptides （boost） was employed to induce higher immune reaction of the mice. The results showed that mice vaccinated with the recombinant plasmid DNA vaccine and boosted with the peptides not only increased the levels of Thl cytokines （IFN-γ and IL-12）, the number of IFN-γ＋ T cells and activities of cytotoxic T lymphocytes as well as IgG, but also enhanced protection against Mycobacterium tuberculosis challenge. In conclusion, these data indicate that the novel recombinant plRES-epitope-peptides-FL plasmid is a useful DNA vaccine for pre- venting Mycobacterium tuberculosis infection.
文摘To construct cDNA library of nasopharyngeal carcinoma （NPC） and obtain the NPC associated or specific antigens from it, we used a powerful new method to identify the antigens eliciting humoral immune response, which is SEREX （serological identification of antigen by recombinant cDNA expression library）. Autologous serum of NPC patient was used to screen the reactive clones in the human NPC tissue cDNA library consisted of 3.64 × 10^6 recombinants. The 23 exact positive clones were subcloned to monoclonality and the size of cDNA inserts was identified by PCR. Then the nucleotide sequence of cDNA inserts was determined, and the sequence alignments were performed with BLAST software on GenBank database. They represented 16 different antigens. A detailed sequence analysis showed that 10 of 16 genes were high homologous to genes known in GenBank, such as RPL31, SI00 A2, MT2A, etc. However, there were also 6 genes with low homology to genes in GenBank. Furthermore, 3 of 6 genes may be novel genes. The associations of these genes to NPC and the roles that they played in the occurrence and development of NPC should be further revealed.
文摘The genes of the heavy and light chain variable region (VH, VL) of Z12 antibody against hTNF-a were cloned, and according to the translated sequence of amino acids, the spa-tial structures of VH and VL domains were modeled by using homology-based modeling method, followed by constructing the whole three-dimensional structure of Fv fragment. The complex model of Fv interacting with hTNF-a was gained with computer-guided molecular docking method, based on which, it was predicted that the epitope recognized by Z12 was from 141 to 146 of hTNF-a. hTNF-a molecule was divided into two fragments of N-terminal region from 1 to 91 and C-terminal region from 92 to 157 with prokaryotic expression. The measured results suggested that the antigenic epitope recognized by Z12 antibody was located in the C-terminal region 92-157 of hTNF-a, proving the predicted result reliable preliminarily. Further experimental results showed that after hTNF- 141-146 residues were deleted, Z12 antibody almost lost the ability to recognize the mutant, suggesting that the amino acid residues from 141 to 146 of hTNF-a were specially recognized by Z12 antibody.
基金grants from National Natural Science Foundation of China(No.81930102 to Bo Yang)Zhejiang Provincial Natural Science Foundation(No.LR22H310002 to Ji Cao,China)Zhejiang University K.P.Chao's High Technology Development Foundation(China)。
文摘Immunoproteasome is a variant of proteasome with structural differences in 20S subunits optimizing them for the production of antigenic peptides with higher binding affinity to major histocompatibility complex(MHC)-I molecules.Apart from this primary function in antigen presentation,immunoproteasome is also responsible for the degradation of proteins,both unfolded proteins for the maintenance of protein homeostasis and tumor suppressor proteins contributing to tumor progression.The altered expression of immunoproteasome is frequently observed in cancers;however,its expression levels and effects vary among different cancer types exhibiting antagonistic roles in tumor development.This review focuses on the dichotomous role of immunoproteasome in different cancer types,as well as summarizes the current progression in immunoproteasome activators and inhibitors.Specifically targeting immunoproteasome may be a beneficial therapeutic intervention in cancer treatment and understanding the role of immunoproteasome in cancers will provide a significant therapeutic insight for the prevention and treatment of cancers.
基金Supported by The Office of the Higher Education Commission and Mahidol University under the National Research Universities Initiative
文摘Different viruses transmit among hosts with different degrees of efficiency. A basic reproductive number(R0) indicates an average number of cases getting infected from a single infected case. R0 can vary widely from a little over 1 to more than 10. Low R0 is usually found among rapidly evolving viruses that are often under a strong positive selection pressure, while high R0 is often found among viruses that are highly stable. The reason for the difference between antigenically diverse viruses with low R0, such as influenza A virus, and antigenically stable viruses with high R0, such as measles virus, is not clear and has been a subject of great interest. Optimization of transmissibility fitness considering intra-host dynamics and inter-host transmissibility was shown to result in strategies for tradeoff between transmissibility and diversity. The nature of transmission, targeting either a na?ve children population or an adult population with partial immunity, has been proposed as a contributing factor for the difference in the strategies used by the two groups of viruses. The R0 determines the levels of threshold heard immunity. Lower R0 requires lowerherd immunity to terminate an outbreak. Therefore, it can be assumed that the outbreak saturation can be reached more readily when the R0 is low. In addition, one may assume that when the outbreak saturation is reached, herd immunity may provide a strong positive selection pressure that could possibly result in an occurrence of escape mutants. Studies of these hypotheses will give us an important insight into viral evolution. This review discusses the above hypotheses as well as some possible mechanistic explanation for the difference in transmission efficiency of
文摘In this study,a synthesized quadruple antigenic epitope gene region of the classical swine fever virus (CSFV)E2 glycoprotein was expressed in E.coli to a obtain target protein.This target protein was used as a coating antigen to establish an indirect ELISA for specifically detecting anti-CSFV antibodies in serum samples from pigs.The P/N cut-off value of this assay was 1.92 by receiver operating characteristic curve(ROC)analysis based on 30 negative sera and 80 positive samples.The test gave 97.5%sensitivity and 96.7%specificity compared with the indirect hemagglutination(IHA)test.The inter-assay and intra-assay coefficients of variation (CVs)for 16 sera were both≤6.8%.No cross-reactivity between the coating antigen and anti-bovine viral diarrhoea virus(BVDV)antibodies was observed.
基金supported by the National Natural Science Foundation of China (31521005, 31672593)the National Key R&D Program of China (2016YFD0500201, 2016YFD0500203)the China Agriculture Research System (CARS-41-G12)
文摘Antigenic drift forces us to frequently update influenza vaccines; however, the genetic basis for antigenic variation remains largely unknown. In this study, we used clade 7.2 H5 viruses as models to explore the molecular determinants of influenza virus antigenic variation. We generated eight monoclonal antibodies(MAbs) targeted to the hemagglutinin(HA) protein of the index virus A/chicken/Shanxi/2/2006 and found that two representative antigenically drifted clade 7.2 viruses did not react with six of the eight MAbs. The E131 N mutation and insertion of leucine at position 134 in the HA protein of the antigenically drifted strains eliminated the reactivity of the virus with the MAbs. We also found that the amino acid N131 in the H5 HA protein is glycosylated. Our results provide experimental evidence that glycosylation and an amino acid insertion or deletion in HA influence antigenic variation.
文摘It is a crucial problem in gene engineering whether an exogenous gene could be correctly expressed in cells of transgenic animal or plant, and how the expression products could be detected quantitatively in translational level. It is very difficult to analyze some gene expression products, such as isopentenyl transferase (ipt), in transgenic investigation because they are trace in organisms. A convenient method is described to determine trace content gene expression product which is hard to purify. The method includes predicting and synthesizing the antigenic peptide according to the cDNA sequence, coupling the synthetic antigenic peptide with carrier protein, raising specific antibodies against the synthetic antigen, and detecting the gene expression product by ELISA and Western blot.
基金supported by grants from the Department of Science and Technology,Government of India (Sanction order No. SR/FT/L-47/2006)
文摘Leptospirosis is recognized as the most widespread zoonosis with a global distribution. In this study, the antigenic variation in Leptospira interrogans and Leptospira borgpetersenii isolated from human urine and field rat kidney was preliminarily confirmed by microscopic agglutination test using monoclonal antibodies, and was further subjected to amplification and identification of outer membrane lipoproreins with structural gene variation. Sequence similarity analysis revealed that these protein sequences, namely OmpL1, LipL32 and LipL41, showed no more homologies to outer membrane lipoproteins of non-pathogenic Leptospira and other closely related Spirochetes, but showed a strong identity within L. interrogans, suggesting intra-specific phylogenetic lineages that might be originated from a common pathogenic leptospiral origin. Moreover, the ompL1 gene showed more antigenic variation than lipL32 and lipL41 due to less conservation in secondary structural evolution within closely related species. Phylogenetically, ompL1 and lipL4l of these strains gave a considerable proximity to L. weilii and L. santaro- sai. The ompI,1 gene of L. interrogans clustered distinctly from other pathogenic and non-pathogenic leptospiral species. The diversity of ompL genes has been an- alyzed and it envisaged that sequence-specific variations at antigenic determinant sites would result in slow evolutionary changes along with new serovar origination within closely related species. Thus, a crucial work on effective recombinant vaccine development and engineered antibodies will hopefully meet to solve the therapeutic challenges.
文摘To investigate the chemical structure of cell wall mannan obtained from pathogenic yeast, Candida tropicalis NBRC 1400 (former antigenic standard strain, IFO 1400). As a result of two-dimensional NMR analysis, it was shown that the mannan of this strain is composed of α-1,6-, α-1,3-, α-1,2- and β-1,2-linked mannose residues. In this research, the mannan was subjected to three degradation procedures, acid-treatment, α-mannosidase, and acetolysis under two conditions in order to determine the chemical structure of the antigenic oligomannosyl side chains in this molecule. The 1H-nuclear magnetic resonance spectra of resultant oligosaccharides, pentaose and hexaose, demonstrated the existence of the oligomannosyl side chains corresponding to Manα1-3Manα1-2Manα1-2Manα1-2Man and Manα1-3Manα1-2Manα1-2Manα1-2Manα1-2Man, respectively, which have previously also been found in Candida albicans serotype A strain mannans. These findings indicate that C. tropicalis and C. albicans serotype A have no significant difference in the chemical structure of these cell wall mannans. Therefore, it can be interpreted that it is extremely difficult to distinguish both species by targeting the antigenic group in these mannans.
