title: Molecular evolution of broadly neutralizing Llama antibodies to the CD4-binding site of HIV-1.
abstract: To date, no immunization of humans or animals has elicited broadly neutralizing sera able to prevent HIV-1 transmission; however, elicitation of broad and potent heavy chain only antibodies (HCAb) has previously been reported in llamas. In this study, the anti-HIV immune responses in immunized llamas were studied via deep sequencing analysis using broadly neutralizing monoclonal HCAbs as a guides. Distinct neutralizing antibody lineages were identified in each animal, including two defined by novel antibodies (as variable regions called VHH) identified by robotic screening of over 6000 clones. The combined application of five VHH against viruses from clades A, B, C and CRF_AG resulted in neutralization as potent as any of the VHH individually and a predicted 100% coverage with a median IC50 of 0.17 µg/ml for the panel of 60 viruses tested. Molecular analysis of the VHH repertoires of two sets of immunized animals showed that each neutralizing lineage was only observed following immunization, demonstrating that they were elicited de novo. Our results show that immunization can induce potent and broadly neutralizing antibodies in llamas with features similar to human antibodies and provide a framework to analyze the effectiveness of immunization protocols.
authors.affiliation: Wohl Virion Centre and Medical Research Council (MRC) Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London, United Kingdom.
authors.forename: Laura E
authors.initials: LE
authors.lastname: McCoy
authors.affiliation: QVQ B.V., Utrecht, The Netherlands.
authors.forename: Lucy
authors.initials: L
authors.lastname: Rutten
authors.affiliation: Wohl Virion Centre and Medical Research Council (MRC) Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London, United Kingdom.
authors.forename: Dan
authors.initials: D
authors.lastname: Frampton
authors.affiliation: Wohl Virion Centre and Medical Research Council (MRC) Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London, United Kingdom.
authors.forename: Ian
authors.initials: I
authors.lastname: Anderson
authors.affiliation: Department of Infectious Diseases, King's College London School of Medicine, Guy's Hospital, London, United Kingdom.
authors.forename: Luke
authors.initials: L
authors.lastname: Granger
authors.affiliation: Wellcome Trust Sanger Institute, Cambridge, United Kingdom.
authors.forename: Rachael
authors.initials: R
authors.lastname: Bashford-Rogers
authors.affiliation: Wohl Virion Centre and Medical Research Council (MRC) Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London, United Kingdom.
authors.forename: Gillian
authors.initials: G
authors.lastname: Dekkers
authors.affiliation: QVQ B.V., Utrecht, The Netherlands.
authors.forename: Nika M
authors.initials: NM
authors.lastname: Strokappe
authors.affiliation: Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Seaman
authors.affiliation: Wohl Virion Centre and Medical Research Council (MRC) Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London, United Kingdom.
authors.forename: Willie
authors.initials: W
authors.lastname: Koh
authors.affiliation: Centro de Virología Animal, Instituto de Ciencia y Tecnología Dr. César Milstein, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
authors.forename: Vanina
authors.initials: V
authors.lastname: Grippo
authors.affiliation: Institute of Medical Microbiology, University of Regensburg, Regensburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kliche
authors.affiliation: QVQ B.V., Utrecht, The Netherlands.
authors.forename: Theo
authors.initials: T
authors.lastname: Verrips
authors.affiliation: Wellcome Trust Sanger Institute, Cambridge, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Kellam
authors.affiliation: Wohl Virion Centre and Medical Research Council (MRC) Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London, United Kingdom.
authors.forename: Ariberto
authors.initials: A
authors.lastname: Fassati
authors.affiliation: Wohl Virion Centre and Medical Research Council (MRC) Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, London, United Kingdom.
authors.forename: Robin A
authors.initials: RA
authors.lastname: Weiss
mesh_terms: D016915:AIDS Vaccines / Q000276:immunology / Q000627:therapeutic use; D000818:Animals; D057134:Antibodies, Neutralizing / Q000235:genetics / Q000276:immunology*; D000956:Antigens, Viral / Q000276:immunology*; D001666:Binding Sites, Antibody / Q000276:immunology*; D015704:CD4 Antigens / Q000276:immunology*; D002161:Camelids, New World / Q000235:genetics / Q000276:immunology*; D004195:Disease Models, Animal; D019143:Evolution, Molecular; D015658:HIV Infections / Q000276:immunology / Q000517:prevention & control; D015497:HIV-1 / Q000276:immunology*; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000276:immunology; D009154:Mutation / Q000235:genetics
chemical_list: D016915:AIDS Vaccines; D057134:Antibodies, Neutralizing; D000956:Antigens, Viral; D015704:CD4 Antigens; D007135:Immunoglobulin Variable Region