title: Immune focusing and enhanced neutralization induced by HIV-1 gp140 chemical cross-linking.
abstract: Experimental vaccine antigens based upon the HIV-1 envelope glycoproteins (Env) have failed to induce neutralizing antibodies (NAbs) against the majority of circulating viral strains as a result of antibody evasion mechanisms, including amino acid variability and conformational instability. A potential vaccine design strategy is to stabilize Env, thereby focusing antibody responses on constitutively exposed, conserved surfaces, such as the CD4 binding site (CD4bs). Here, we show that a largely trimeric form of soluble Env can be stably cross-linked with glutaraldehyde (GLA) without global modification of antigenicity. Cross-linking largely conserved binding of all potent broadly neutralizing antibodies (bNAbs) tested, including CD4bs-specific VRC01 and HJ16, but reduced binding of several non- or weakly neutralizing antibodies and soluble CD4 (sCD4). Adjuvanted administration of cross-linked or unmodified gp140 to rabbits generated indistinguishable total gp140-specific serum IgG binding titers. However, sera from animals receiving cross-linked gp140 showed significantly increased CD4bs-specific antibody binding compared to animals receiving unmodified gp140. Moreover, peptide mapping of sera from animals receiving cross-linked gp140 revealed increased binding to gp120 C1 and V1V2 regions. Finally, neutralization titers were significantly elevated in sera from animals receiving cross-linked gp140 rather than unmodified gp140. We conclude that cross-linking favors antigen stability, imparts antigenic modifications that selectively refocus antibody specificity and improves induction of NAbs, and might be a useful strategy for future vaccine design.
authors.affiliation: The Sir William Dunn School of Pathology, Oxford, United Kingdom.
authors.forename: T
authors.initials: T
authors.lastname: Schiffner
authors.forename: L
authors.initials: L
authors.lastname: Kong
authors.forename: C J A
authors.initials: CJ
authors.lastname: Duncan
authors.forename: J W
authors.initials: JW
authors.lastname: Back
authors.forename: J J
authors.initials: JJ
authors.lastname: Benschop
authors.forename: X
authors.initials: X
authors.lastname: Shen
authors.forename: P S
authors.initials: PS
authors.lastname: Huang
authors.forename: G B
authors.initials: GB
authors.lastname: Stewart-Jones
authors.forename: J
authors.initials: J
authors.lastname: DeStefano
authors.forename: M S
authors.initials: MS
authors.lastname: Seaman
authors.forename: G D
authors.initials: GD
authors.lastname: Tomaras
authors.forename: D C
authors.initials: DC
authors.lastname: Montefiori
authors.forename: W R
authors.initials: WR
authors.lastname: Schief
authors.forename: Q J
authors.initials: QJ
authors.lastname: Sattentau
mesh_terms: D016915:AIDS Vaccines / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood*; D003432:Cross-Linking Reagents / Q000378:metabolism; D015483:HIV Antibodies / Q000097:blood*; D015488:HIV Antigens / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D011817:Rabbits; D054299:env Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism
chemical_list: D016915:AIDS Vaccines; D000276:Adjuvants, Immunologic; D057134:Antibodies, Neutralizing; D003432:Cross-Linking Reagents; D015483:HIV Antibodies; D015488:HIV Antigens; D054299:env Gene Products, Human Immunodeficiency Virus; C097729:gp140 envelope protein, Human immunodeficiency virus 1