Hepatitis E virus （HEV） genotype 4 was originally identified in China. Its neutralization antigenic epitopes have not been characterized. Recently, we identified a neutralizing monoclonal antibody （mAb） IG10, whic...Hepatitis E virus （HEV） genotype 4 was originally identified in China. Its neutralization antigenic epitopes have not been characterized. Recently, we identified a neutralizing monoclonal antibody （mAb） IG10, which was generated following immunization of mice with p166Chn, a recombinant protein comprising 464-629 amino acids （aa） of the HEV genotype 4 capsid protein. In this study, a panel of 22 N- and/or C-terminal truncated and 6 site-directed mutated p166Chn proteins were prepared. Only those N- or C-terminal truncated proteins containing the region 477-613 aa could react with the mAb 1G10, suggesting the neutralization epitope of HEV genotype 4 is located between aa477 and aa613. However, a both N- and C-terminal truncated protein, pN477-C613, neither reacted to 1G10 nor elicited neutralizing antibodies in mice, while another both terminal truncated protein, pN472-C617, did, suggesting the flanking regions of the pN477-C613 could help to stabilize and allow presentation of the neutralization epitope to the immune system. Substituting Leu477 and/or Leu613 with the polar, uncharged threonine （Thr） caused 〉 50% reduction of the mutants＇ immunoreactivity to IG10, whereas replacement by hydrophobic phenylalanine （Phe） made little impact on the immunoreactivity, revealing functional associations between hydrophobicity of aa at positions 477 and 613 and the antigenicity of p166Chn. These data suggested Leu477 and Leu613 are critical in forming the neutralization epitope of HEV genotype 4. Cellular ＆ Molecular Immunology. 2008;5（6）：447-456.展开更多
Some neutralizing antibodies against HIV-1 envelope proteins were highly effective to inhibit the infection of different strains in vitro, and existed in the infected individuals with very low levels. We suggested mul...Some neutralizing antibodies against HIV-1 envelope proteins were highly effective to inhibit the infection of different strains in vitro, and existed in the infected individuals with very low levels. We suggested multi-epi-tope-vaccine as a new strategy to increase levels of neutralizing antibodies and the abilities against HIV mutation in vivo. Two candidate multi-epitope-vaccines induced antibodies with predefined multi-epitope-specificity in rhesus macaque. These antibodies recognized corresponding neutralizing epitopes on epitope-peptides, gp41 peptides, V3 loop peptide, rsgp41 and rgp120. Besides, three candidate epi-tope-vaccines in combination (another kind of multi-epitope-vaccines) showed similar potency to induce predefined multiple immune responses in rabbits. These results suggest thatmulti-epitope-vaccines may be a new strategy to induce multi-antiviral activities against HIV-1 infection and mutations.展开更多
Background Studies on human immunodeficiency virus type 1 （HIV-1） vaccines have recently focused on targeting the conserved neutralizing epitopes 2F5 and 4E10, and hence it is important to understand the extent of m...Background Studies on human immunodeficiency virus type 1 （HIV-1） vaccines have recently focused on targeting the conserved neutralizing epitopes 2F5 and 4E10, and hence it is important to understand the extent of mutations in these two viral epitopes. Here, we investigated the amino acid mutations in epitopes of 2F5 （ELDKWA, HIV-1 HXB2 env 662-667 aa） and 4E10 （NWFDIT, HIV-1 HXB2 env 671-676 aa） in the membrane proximal-external region of gp41 from clade B＇ HIV-1-infected individuals living in Henan province, China. We also examined the frequency of a mutation and its relation to disease progression.Methods A cohort of 54 treatment-na（i）ve HIV-1-infected individuals was recruited in this study, and 16 individuals were selected for a short-term longitudinal study on sequence evolution. The HIV-1 env gp41 gene was amplified, cloned, and sequenced, and predicted amino acid sequences were aligned for analysis.Results The mutations E662A and K665E on the 2F5 epitope and N671S and T676S on the 4E10 epitope were seen.Simultaneous RNA sequencing showed some discrepancies with proviral DNA sequences. In our longitudinal study,mutation levels of these two neutralizing epitopes were low but diverse and persistent. The frequencies of mutations within the 4E10 peptide NWFDIT in slow progressors were noticeably lower than those in AIDS patients （P ＜0.05）.Conclusions Antigenic variation of the neutralizing epitopes 2F5 and 4E10 is limited in subtype B＇ infection, and that 4E10 peptide mutation is correlated with disease progression. Monitoring epitope mutations will offer useful data for development of the candidate 2F5-like and 4E10-like antibodies to prevent and treat AIDS.展开更多
In this present study, we predicted the neutralizing epitope of a modeled H5N1 hemagglutinin 1046T when interacted with a modeled monoclonal antibody variable fragment 8H5Fv using molecular dynamics simulation. Follow...In this present study, we predicted the neutralizing epitope of a modeled H5N1 hemagglutinin 1046T when interacted with a modeled monoclonal antibody variable fragment 8H5Fv using molecular dynamics simulation. Following the production run of the molecular dynamics simulation, we observed the average change of solvent accessible surface of the antigen alongside the formation of hydrogen bonds between the two structures during the simulation. Based on the acquired data, we predicted the neutralizing epitope of the 1046T antigen to be consisted of residues Asp 84, Glu85, Phe86, Ile87, Asn88, Val89, Pro90, Ile132, Ser136, Val147, Pro152, Tyr153, Leu154, Arg161, and Tyr268. By calculating the RMSD of the Cα backbone chain of the complex during the simulation we found the structure to be generally stable suggesting a well maintained steric hindrance, while RMSD calculation of the predicted neutralizing epitope backbone suggests the stability of the neutralizing epitope itself.展开更多
基金supported by grants from the National Natural Science Foundation of China (No. 30271231, No. 30671858)the High Technology Research Program of Jiangsu Province, China (BG2006607)partially supported by the National High Technology Research and Development Program of China (863 Program, 2006AA02A235)
文摘Hepatitis E virus （HEV） genotype 4 was originally identified in China. Its neutralization antigenic epitopes have not been characterized. Recently, we identified a neutralizing monoclonal antibody （mAb） IG10, which was generated following immunization of mice with p166Chn, a recombinant protein comprising 464-629 amino acids （aa） of the HEV genotype 4 capsid protein. In this study, a panel of 22 N- and/or C-terminal truncated and 6 site-directed mutated p166Chn proteins were prepared. Only those N- or C-terminal truncated proteins containing the region 477-613 aa could react with the mAb 1G10, suggesting the neutralization epitope of HEV genotype 4 is located between aa477 and aa613. However, a both N- and C-terminal truncated protein, pN477-C613, neither reacted to 1G10 nor elicited neutralizing antibodies in mice, while another both terminal truncated protein, pN472-C617, did, suggesting the flanking regions of the pN477-C613 could help to stabilize and allow presentation of the neutralization epitope to the immune system. Substituting Leu477 and/or Leu613 with the polar, uncharged threonine （Thr） caused 〉 50% reduction of the mutants＇ immunoreactivity to IG10, whereas replacement by hydrophobic phenylalanine （Phe） made little impact on the immunoreactivity, revealing functional associations between hydrophobicity of aa at positions 477 and 613 and the antigenicity of p166Chn. These data suggested Leu477 and Leu613 are critical in forming the neutralization epitope of HEV genotype 4. Cellular ＆ Molecular Immunology. 2008;5（6）：447-456.
基金This work was supported by the National KeyBasic Research Specific Funds (Grant No. G1999054107) the Na- tional Science Foundation for Outstanding Young Scientists of China (Grant No. 30025038).
文摘Some neutralizing antibodies against HIV-1 envelope proteins were highly effective to inhibit the infection of different strains in vitro, and existed in the infected individuals with very low levels. We suggested multi-epi-tope-vaccine as a new strategy to increase levels of neutralizing antibodies and the abilities against HIV mutation in vivo. Two candidate multi-epitope-vaccines induced antibodies with predefined multi-epitope-specificity in rhesus macaque. These antibodies recognized corresponding neutralizing epitopes on epitope-peptides, gp41 peptides, V3 loop peptide, rsgp41 and rgp120. Besides, three candidate epi-tope-vaccines in combination (another kind of multi-epitope-vaccines) showed similar potency to induce predefined multiple immune responses in rabbits. These results suggest thatmulti-epitope-vaccines may be a new strategy to induce multi-antiviral activities against HIV-1 infection and mutations.
文摘Background Studies on human immunodeficiency virus type 1 （HIV-1） vaccines have recently focused on targeting the conserved neutralizing epitopes 2F5 and 4E10, and hence it is important to understand the extent of mutations in these two viral epitopes. Here, we investigated the amino acid mutations in epitopes of 2F5 （ELDKWA, HIV-1 HXB2 env 662-667 aa） and 4E10 （NWFDIT, HIV-1 HXB2 env 671-676 aa） in the membrane proximal-external region of gp41 from clade B＇ HIV-1-infected individuals living in Henan province, China. We also examined the frequency of a mutation and its relation to disease progression.Methods A cohort of 54 treatment-na（i）ve HIV-1-infected individuals was recruited in this study, and 16 individuals were selected for a short-term longitudinal study on sequence evolution. The HIV-1 env gp41 gene was amplified, cloned, and sequenced, and predicted amino acid sequences were aligned for analysis.Results The mutations E662A and K665E on the 2F5 epitope and N671S and T676S on the 4E10 epitope were seen.Simultaneous RNA sequencing showed some discrepancies with proviral DNA sequences. In our longitudinal study,mutation levels of these two neutralizing epitopes were low but diverse and persistent. The frequencies of mutations within the 4E10 peptide NWFDIT in slow progressors were noticeably lower than those in AIDS patients （P ＜0.05）.Conclusions Antigenic variation of the neutralizing epitopes 2F5 and 4E10 is limited in subtype B＇ infection, and that 4E10 peptide mutation is correlated with disease progression. Monitoring epitope mutations will offer useful data for development of the candidate 2F5-like and 4E10-like antibodies to prevent and treat AIDS.
文摘In this present study, we predicted the neutralizing epitope of a modeled H5N1 hemagglutinin 1046T when interacted with a modeled monoclonal antibody variable fragment 8H5Fv using molecular dynamics simulation. Following the production run of the molecular dynamics simulation, we observed the average change of solvent accessible surface of the antigen alongside the formation of hydrogen bonds between the two structures during the simulation. Based on the acquired data, we predicted the neutralizing epitope of the 1046T antigen to be consisted of residues Asp 84, Glu85, Phe86, Ile87, Asn88, Val89, Pro90, Ile132, Ser136, Val147, Pro152, Tyr153, Leu154, Arg161, and Tyr268. By calculating the RMSD of the Cα backbone chain of the complex during the simulation we found the structure to be generally stable suggesting a well maintained steric hindrance, while RMSD calculation of the predicted neutralizing epitope backbone suggests the stability of the neutralizing epitope itself.
