Induction of broadly neutralizing monoclonal antibodies(bNAbs)that bind to the viral envelope glycoproteins is a major goal of hepatitis C virus(HCV)vaccine research.The study of bNAbs arising in natural infection is ...Induction of broadly neutralizing monoclonal antibodies(bNAbs)that bind to the viral envelope glycoproteins is a major goal of hepatitis C virus(HCV)vaccine research.The study of bNAbs arising in natural infection is essential in this endeavor.We generated a human antibody,8D6,recognizing the E2 protein of HCV isolated from a chronic hepatitis C patient.This antibody shows broadly neutralizing activity,which covers a pan-genotypic panel of cell culture-derived HCV virions(HCVcc).Functional and epitope analyses demonstrated that 8D6 can block the interaction between E2 and CD81 by targeting a highly conserved epitope on E2.We describe how the 8D6 lineage evolved via somatic hypermutation to achieve broad neutralization.We found that the V(D)J recombination-generated junctional and somatic hypermutation-induced disulfide bridge(C-C)motif in the CDRH3 is critical for the broad neutralization and binding activity of 8D6.This motif is conserved among a series of broadly neutralizing HCV antibodies,indicating a common binding model.Next,the 8D6 inferred germline(iGL)was reconstructed and tested for its binding affinity and neutralization activity.Interestingly,8D6 iGL-mediated relatively strong inhibition of the 1b genotype PR79L9 strain,suggesting that PR79L9 may serve as a potential natural viral strain that provides E2 sequences that induce bNAbs.Overall,our detailed epitope mapping and genetic studies of the HCV E2-specific mAb 8D6 have allowed for further refinement of antigenic sites on E2 and reveal a new mechanism to generate a functional CDRH3,while its iGL can serve as a probe to identify potential HCV vaccine strains.展开更多
In the bone marrow and spleen,the developing B cell populations undergo both negative and positive selections to shape their B cell receptor repertoire.To gain insight into the shift of the immunoglobulin heavy(IgH)ch...In the bone marrow and spleen,the developing B cell populations undergo both negative and positive selections to shape their B cell receptor repertoire.To gain insight into the shift of the immunoglobulin heavy(IgH)chain repertoire during B cell development,we undertook large scale Igμchain repertoire analysis of pre-B,immature B and spleen B cell populations.We found that the majority of VH gene segments,VH families,JH and D gene segments,were observed to have significantly different usage frequencies when three B cell populations were compared,but the usage profile of the VH,D,and JH genes between different B cell populations showed high correlations.In both productive and nonproductive rearrangements,the length of CDRH3 shortened significantly on average when B cells entered the periphery.However,the CDRH3 length distribution of nonproductive rearrangements did not follow a Gaussian distribution,but decreased successively in the order 3n–2,3n–1 and 3n,suggesting a direct correlation between mRNA stability and CDRH3 length patterns of nonproductive rearrangements.Further analysis of the individual components comprising CDRH3 of productive rearrangements indicated that the decrease in CDRH3 length was largely due to the reduction of N addition at the 5′and 3′junctions.Moreover,with development,the amino acid content of CDRH3 progressed toward fewer positively charged and nonpolar residues but more polar residues.All these data indicated that the expressed Igμchain repertoire,especially the repertoire of CDRH3,was fine-tuned when B cells passed through several checkpoints of selection during the process of maturation.展开更多
基金supported by grants from the Chinese National 973 Program(2015CB554302)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB19000000)to B.S.+4 种基金the Chinese National 973 Program(2015CB554300)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB29010205)to M.the National Natural Science Foundation of China(31670172)Shanghai Science and Technology Innovation Action(16DZ1910100)to B.S.Nanjing Galaxy Biopharma C.O.
文摘Induction of broadly neutralizing monoclonal antibodies(bNAbs)that bind to the viral envelope glycoproteins is a major goal of hepatitis C virus(HCV)vaccine research.The study of bNAbs arising in natural infection is essential in this endeavor.We generated a human antibody,8D6,recognizing the E2 protein of HCV isolated from a chronic hepatitis C patient.This antibody shows broadly neutralizing activity,which covers a pan-genotypic panel of cell culture-derived HCV virions(HCVcc).Functional and epitope analyses demonstrated that 8D6 can block the interaction between E2 and CD81 by targeting a highly conserved epitope on E2.We describe how the 8D6 lineage evolved via somatic hypermutation to achieve broad neutralization.We found that the V(D)J recombination-generated junctional and somatic hypermutation-induced disulfide bridge(C-C)motif in the CDRH3 is critical for the broad neutralization and binding activity of 8D6.This motif is conserved among a series of broadly neutralizing HCV antibodies,indicating a common binding model.Next,the 8D6 inferred germline(iGL)was reconstructed and tested for its binding affinity and neutralization activity.Interestingly,8D6 iGL-mediated relatively strong inhibition of the 1b genotype PR79L9 strain,suggesting that PR79L9 may serve as a potential natural viral strain that provides E2 sequences that induce bNAbs.Overall,our detailed epitope mapping and genetic studies of the HCV E2-specific mAb 8D6 have allowed for further refinement of antigenic sites on E2 and reveal a new mechanism to generate a functional CDRH3,while its iGL can serve as a probe to identify potential HCV vaccine strains.
基金This work was supported by the National Basic Research Program of China(2010CB945300).
文摘In the bone marrow and spleen,the developing B cell populations undergo both negative and positive selections to shape their B cell receptor repertoire.To gain insight into the shift of the immunoglobulin heavy(IgH)chain repertoire during B cell development,we undertook large scale Igμchain repertoire analysis of pre-B,immature B and spleen B cell populations.We found that the majority of VH gene segments,VH families,JH and D gene segments,were observed to have significantly different usage frequencies when three B cell populations were compared,but the usage profile of the VH,D,and JH genes between different B cell populations showed high correlations.In both productive and nonproductive rearrangements,the length of CDRH3 shortened significantly on average when B cells entered the periphery.However,the CDRH3 length distribution of nonproductive rearrangements did not follow a Gaussian distribution,but decreased successively in the order 3n–2,3n–1 and 3n,suggesting a direct correlation between mRNA stability and CDRH3 length patterns of nonproductive rearrangements.Further analysis of the individual components comprising CDRH3 of productive rearrangements indicated that the decrease in CDRH3 length was largely due to the reduction of N addition at the 5′and 3′junctions.Moreover,with development,the amino acid content of CDRH3 progressed toward fewer positively charged and nonpolar residues but more polar residues.All these data indicated that the expressed Igμchain repertoire,especially the repertoire of CDRH3,was fine-tuned when B cells passed through several checkpoints of selection during the process of maturation.
