title: Dengue virus envelope domain III immunization elicits predominantly cross-reactive, poorly neutralizing antibodies localized to the AB loop: implications for dengue vaccine design.
abstract: Dengue virus (DENV) is a mosquito-borne virus that causes severe health problems. An effective tetravalent dengue vaccine candidate that can provide life-long protection simultaneously against all four DENV serotypes is highly anticipated. A better understanding of the antibody response to DENV envelope protein domain III (EDIII) may offer insights into vaccine development. Here, we identified 25 DENV cross-reactive mAbs from immunization with Pichia pastoris-expressed EDIII of a single or all four serotype(s) using a prime-boost protocol, and through pepscan analysis found that 60 % of them (15/25) specifically recognized the same highly conserved linear epitope aa 309-320 of EDIII. All 15 complex-reactive mAbs exhibited significant cross-reactivity with recombinant EDIII from all DENV serotypes and also with C6/36 cells infected with DENV-1, -2, -3 and -4. However, neutralization assays indicated that the majority of these 15 mAbs were either moderately or weakly neutralizing. Through further epitope mapping by yeast surface display, two residues in the AB loop, Q316 and H317, were discovered to be critical. Three-dimensional modelling analysis suggests that this epitope is surface exposed on EDIII but less accessible on the surface of the E protein dimer and trimer, especially on the surface of the mature virion. It is concluded that EDIII as an immunogen may elicit cross-reactive mAbs toward an epitope that is not exposed on the virion surface, therefore contributing inefficiently to the mAbs neutralization potency. Therefore, the prime-boost strategy of EDIII from a single serotype or four serotypes mainly elicited a poorly neutralizing, cross-reactive antibody response to the conserved AB loop of EDIII.
authors.affiliation: Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Guangzhou Center for Disease Control and Prevention, Guangzhou 510440, PR China.
authors.forename: Xiao-Quan
authors.initials: XQ
authors.lastname: Li
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Li-Wen
authors.initials: LW
authors.lastname: Qiu
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Kun
authors.initials: K
authors.lastname: Wen
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Jian-Piao
authors.initials: JP
authors.lastname: Cai
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Yu-Xian
authors.initials: YX
authors.lastname: Pan
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Hu
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Yan-Fen
authors.initials: YF
authors.lastname: Huang
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Li-Dong
authors.initials: LD
authors.lastname: Liu
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Xi-Xia
authors.initials: XX
authors.lastname: Ding
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Yong-Hui
authors.initials: YH
authors.lastname: Guo
authors.affiliation: Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.|Laboratory of Emerging Infectious Diseases, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, PR China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Che
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000911:Antibodies, Monoclonal / Q000276:immunology; D057134:Antibodies, Neutralizing / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology*; D003429:Cross Reactions; D053059:Dengue Vaccines / Q000737:chemistry / Q000276:immunology*; D003716:Dengue Virus / Q000276:immunology* / Q000378:metabolism; D018604:Epitope Mapping; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D008958:Models, Molecular; D010843:Pichia / Q000378:metabolism; D017434:Protein Structure, Tertiary; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D053059:Dengue Vaccines; D000939:Epitopes; D014759:Viral Envelope Proteins