title: A gp41 MPER-specific llama VHH requires a hydrophobic CDR3 for neutralization but not for antigen recognition.
abstract: The membrane proximal external region (MPER) of the HIV-1 glycoprotein gp41 is targeted by the broadly neutralizing antibodies 2F5 and 4E10. To date, no immunization regimen in animals or humans has produced HIV-1 neutralizing MPER-specific antibodies. We immunized llamas with gp41-MPER proteoliposomes and selected a MPER-specific single chain antibody (VHH), 2H10, whose epitope overlaps with that of mAb 2F5. Bi-2H10, a bivalent form of 2H10, which displayed an approximately 20-fold increased affinity compared to the monovalent 2H10, neutralized various sensitive and resistant HIV-1 strains, as well as SHIV strains in TZM-bl cells. X-ray and NMR analyses combined with mutagenesis and modeling revealed that 2H10 recognizes its gp41 epitope in a helical conformation. Notably, tryptophan 100 at the tip of the long CDR3 is not required for gp41 interaction but essential for neutralization. Thus bi-2H10 is an anti-MPER antibody generated by immunization that requires hydrophobic CDR3 determinants in addition to epitope recognition for neutralization similar to the mode of neutralization employed by mAbs 2F5 and 4E10.
authors.affiliation: Unit of Virus Host Cell Interactions (UVHCI), UMI 3265, Université Joseph Fourier-EMBL-CNRS, Grenoble, France.
authors.forename: David
authors.initials: D
authors.lastname: Lutje Hulsik
authors.forename: Ying-ying
authors.initials: YY
authors.lastname: Liu
authors.forename: Nika M
authors.initials: NM
authors.lastname: Strokappe
authors.forename: Simone
authors.initials: S
authors.lastname: Battella
authors.forename: Mohamed
authors.initials: M
authors.lastname: El Khattabi
authors.forename: Laura E
authors.initials: LE
authors.lastname: McCoy
authors.forename: Charles
authors.initials: C
authors.lastname: Sabin
authors.forename: Andreas
authors.initials: A
authors.lastname: Hinz
authors.forename: Miriam
authors.initials: M
authors.lastname: Hock
authors.forename: Pauline
authors.initials: P
authors.lastname: Macheboeuf
authors.forename: Alexandre M J J
authors.initials: AM
authors.lastname: Bonvin
authors.forename: Johannes P M
authors.initials: JP
authors.lastname: Langedijk
authors.forename: David
authors.initials: D
authors.lastname: Davis
authors.forename: Anna
authors.initials: A
authors.lastname: Forsman Quigley
authors.forename: Marlén M I
authors.initials: MM
authors.lastname: Aasa-Chapman
authors.forename: Michael S
authors.initials: MS
authors.lastname: Seaman
authors.forename: Alejandra
authors.initials: A
authors.lastname: Ramos
authors.forename: Pascal
authors.initials: P
authors.lastname: Poignard
authors.forename: Adrien
authors.initials: A
authors.lastname: Favier
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Simorre
authors.forename: Robin A
authors.initials: RA
authors.lastname: Weiss
authors.forename: C Theo
authors.initials: CT
authors.lastname: Verrips
authors.forename: Winfried
authors.initials: W
authors.lastname: Weissenhorn
authors.forename: Lucy
authors.initials: L
authors.lastname: Rutten
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology*; D001483:Base Sequence; D002161:Camelids, New World / Q000276:immunology*; D002460:Cell Line; D022801:Complementarity Determining Regions / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D015483:HIV Antibodies / Q000276:immunology*; D015700:HIV Envelope Protein gp41 / Q000276:immunology*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007114:Immunization; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009500:Neutralization Tests; D011510:Proteolipids / Q000008:administration & dosage / Q000276:immunology; D061905:Single-Domain Antibodies; D020349:Surface Plasmon Resonance
chemical_list: D057134:Antibodies, Neutralizing; D022801:Complementarity Determining Regions; D000939:Epitopes; D015483:HIV Antibodies; D015700:HIV Envelope Protein gp41; D011510:Proteolipids; D061905:Single-Domain Antibodies; C020485:proteoliposomes