title: Differential Antibody Responses to Conserved HIV-1 Neutralizing Epitopes in the Context of Multivalent Scaffolds and Native-Like gp140 Trimers.
abstract: Broadly neutralizing antibodies (bNAbs) have provided valuable insights into the humoral immune response to HIV-1. While rationally designed epitope scaffolds and well-folded gp140 trimers have been proposed as vaccine antigens, a comparative understanding of their antibody responses has not yet been established. In this study, we probed antibody responses to the N332 supersite and the membrane-proximal external region (MPER) in the context of heterologous protein scaffolds and native-like gp140 trimers. Ferritin nanoparticles and fragment crystallizable (Fc) regions were utilized as multivalent carriers to display scaffold antigens with grafted N332 and MPER epitopes, respectively. Trimeric scaffolds were also identified to stabilize the MPER-containing BG505 gp140.681 trimer in a native-like conformation. Following structural and antigenic evaluation, a subset of scaffold and trimer antigens was selected for immunization in BALB/c mice. Serum binding revealed distinct patterns of antibody responses to these two bNAb targets presented in different structural contexts. For example, the N332 nanoparticles elicited glycan epitope-specific antibody responses that could also recognize the native trimer, while a scaffolded BG505 gp140.681 trimer generated a stronger and more rapid antibody response to the trimer apex than its parent gp140.664 trimer. Furthermore, next-generation sequencing (NGS) of mouse splenic B cells revealed expansion of antibody lineages with long heavy-chain complementarity-determining region 3 (HCDR3) loops upon activation by MPER scaffolds, in contrast to the steady repertoires primed by N332 nanoparticles and a soluble gp140.664 trimer. These findings will facilitate the future development of a coherent vaccination strategy that combines both epitope-focused and trimer-based approaches.IMPORTANCEBoth epitope-focused and trimer-based strategies are currently being explored in HIV-1 vaccine development, which aims to elicit broadly neutralizing antibodies (bNAbs) targeting conserved epitopes on the viral envelope (Env). However, little is known about the differences in antibody response to these bNAb targets presented by foreign scaffolds and native Env. In this study, a systematic effort was undertaken to design multivalent epitope scaffolds and soluble gp140.681 trimers with a complete antigenic surface, and to comparatively analyze the antibody responses elicited by these antigens to the N332 supersite and MPER in a mouse model. This study will inform both epitope-focused and trimer-based vaccine design and will facilitate integration of the two vaccine strategies.
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Charles D
authors.initials: CD
authors.lastname: Morris
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Parisa
authors.initials: P
authors.lastname: Azadnia
authors.affiliation: Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA.|International AIDS Vaccine Initiative, Neutralizing Antibody Center and the Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California, USA.|Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Natalia
authors.initials: N
authors.lastname: de Val
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Nemil
authors.initials: N
authors.lastname: Vora
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Honda
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Erick
authors.initials: E
authors.lastname: Giang
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.|Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Saye-Francisco
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Yushao
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Xiaohe
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Mann
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.|International AIDS Vaccine Initiative, Neutralizing Antibody Center and the Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California, USA.|Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Devin
authors.initials: D
authors.lastname: Sok
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.|International AIDS Vaccine Initiative, Neutralizing Antibody Center and the Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California, USA.|Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, USA.|Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts, USA.
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Burton
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Mansun
authors.initials: M
authors.lastname: Law
authors.affiliation: Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA.|International AIDS Vaccine Initiative, Neutralizing Antibody Center and the Collaboration for AIDS Vaccine Discovery, The Scripps Research Institute, La Jolla, California, USA.|Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Ward
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA linling@scripps.edu jiang@scripps.edu.
authors.forename: Linling
authors.initials: L
authors.lastname: He
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, USA linling@scripps.edu jiang@scripps.edu.|Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA.|Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhu
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood*; D000917:Antibody Formation; D000939:Epitopes / Q000276:immunology*; D015483:HIV Antibodies / Q000097:blood*; D051379:Mice; D008807:Mice, Inbred BALB C; D054299:env Gene Products, Human Immunodeficiency Virus / Q000276:immunology*
chemical_list: D057134:Antibodies, Neutralizing; D000939:Epitopes; D015483:HIV Antibodies; D054299:env Gene Products, Human Immunodeficiency Virus; C097729:gp140 envelope protein, Human immunodeficiency virus 1