title: Mechanisms of escape from the PGT128 family of anti-HIV broadly neutralizing antibodies.
abstract: BACKGROUND
  Broadly neutralizing antibodies (bnAbs) directed against the mannose-patch on the HIV envelope glycoprotein gp120 have several features that make them desirable targets for vaccine design. The PGT125-131 bnAb family is of particular interest due to its superior breadth and potency. The overlapping epitopes recognized by this family are intricate and neutralization requires interaction with at least two N-linked glycans (N332/N334, N295 or N301) in addition to backbone-mediated contact with the (323)IGDIR(327) motif of the V3 loop. We have recently shown that this bnAb family consists of two distinct antibody classes that can bind alternate arrangements of glycans in the mannose-patch in the absence of N332 thereby limiting viral escape. This led us to further investigate viral resistance and escape mechanisms to the PGT125-131 bnAb family.
  
  
  RESULTS
  Using an escape virus isolated from the PGT125-131 donor as a guide, we show that mutating both the V3 core protein epitope and repositioning critical N-linked glycosylation sites are required to restore neutralization sensitivity. Interestingly, neutralization sensitivity could be restored via different routes for the two distinct bnAb classes within the PGT125-131 family, which may have been important in generating the divergence in recognition. We demonstrate that the observed V3 mutations confer neutralization resistance in other virus strains through both gain-of-function and escape studies. Furthermore, we show that the V3 loop is important in facilitating promiscuous binding to glycans within the mannose-patch.
  
  
  CONCLUSIONS
  These data highlight the importance of the V3 loop in the design of immunogens aimed at inducing broad and potent bnAbs that can bind promiscuously to the mannose-patch.
authors.affiliation: Department of Infectious Diseases, King's College London School of Medicine, Guy's Hospital, Great Maze Pond, London, SE1 9RT, UK. stefanie.krumm@kcl.ac.uk.
authors.forename: Stefanie A
authors.initials: SA
authors.lastname: Krumm
authors.affiliation: Department of Infectious Diseases, King's College London School of Medicine, Guy's Hospital, Great Maze Pond, London, SE1 9RT, UK. hajer.mohammed@kcl.ac.uk.
authors.forename: Hajer
authors.initials: H
authors.lastname: Mohammed
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA. khoale@scripps.edu.|IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, USA. khoale@scripps.edu.|Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA, USA. khoale@scripps.edu.
authors.forename: Khoa M
authors.initials: KM
authors.lastname: Le
authors.affiliation: Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK. max.crispin@bioch.ox.ac.uk.
authors.forename: Max
authors.initials: M
authors.lastname: Crispin
authors.affiliation: Monogram Biosciences, Laboratory Corporation of America(R) Holdings, South San Francisco, CA, USA. wrint@labcorp.com.
authors.forename: Terri
authors.initials: T
authors.lastname: Wrin
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA. poignard@scripps.edu.|IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, USA. poignard@scripps.edu.
authors.forename: Pascal
authors.initials: P
authors.lastname: Poignard
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA. burton@scripps.edu.|IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, USA. burton@scripps.edu.|Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA, USA. burton@scripps.edu.|Ragon Institute of MGH, MIT and Harvard, Cambridge, USA. burton@scripps.edu.
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Burton
authors.affiliation: Department of Infectious Diseases, King's College London School of Medicine, Guy's Hospital, Great Maze Pond, London, SE1 9RT, UK. katie.doores@kcl.ac.uk.
authors.forename: Katie J
authors.initials: KJ
authors.lastname: Doores
mesh_terms: D057134:Antibodies, Neutralizing / Q000276:immunology*; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D006678:HIV / Q000276:immunology*; D015483:HIV Antibodies / Q000276:immunology*; D015699:HIV Envelope Protein gp120 / Q000276:immunology*; D006801:Humans; D057131:Immune Evasion; D009154:Mutation; D011134:Polysaccharides / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D018985:Epitopes, B-Lymphocyte; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; D011134:Polysaccharides
references.citation: Nat Rev Immunol. 2013 Sep;13(9):693-701
references.pmid: 23969737
references.citation: J Virol. 2013 Aug;87(15):8798-804
references.pmid: 23720719
references.citation: PLoS Pathog. 2013;9(11):e1003754
references.pmid: 24278016
references.citation: Nature. 2014 May 1;509(7498):55-62
references.pmid: 24590074
references.citation: Sci Transl Med. 2014 May 14;6(236):236ra63
references.pmid: 24828077
references.citation: Immunity. 2014 May 15;40(5):657-68
references.pmid: 24768347
references.citation: PLoS One. 2014;9(7):e99881
references.pmid: 24992528
references.citation: Cell. 2014 Jul 31;158(3):481-91
references.pmid: 25065977
references.citation: J Exp Med. 2014 Sep 22;211(10):2061-74
references.pmid: 25155019
references.citation: Cell. 2014 Sep 25;159(1):69-79
references.pmid: 25259921
references.citation: J Virol. 2015 Jan 15;89(2):1105-18
references.pmid: 25378488
references.citation: Curr Opin Virol. 2015 Apr;11:63-9
references.pmid: 25747313
references.citation: J Virol. 2015 Jul;89(13):6952-9
references.pmid: 25878100
references.citation: Structure. 2015 Oct 6;23(10):1943-51
references.pmid: 26388028
references.citation: Acta Crystallogr D Biol Crystallogr. 2015 Oct;71(Pt 10):2099-108
references.pmid: 26457433
references.citation: Immunity. 2015 Dec 15;43(6):1053-63
references.pmid: 26682982
references.citation: J Acquir Immune Defic Syndr. 2007 Sep 1;46(1):1-11
references.pmid: 17514017
references.citation: J Virol. 2005 Aug;79(16):10108-25
references.pmid: 16051804
references.citation: FEBS J. 2015 Dec;282(24):4679-91
references.pmid: 26411545
references.citation: Curr Protoc Immunol. 2005 Jan;Chapter 12:Unit 12.11
references.pmid: 18432938
references.citation: PLoS Pathog. 2009 May;5(5):e1000433
references.pmid: 19436712
references.citation: J Virol. 2009 Jul;83(14):7337-48
references.pmid: 19439467
references.citation: Nat Med. 2009 Aug;15(8):951-4
references.pmid: 19525965
references.citation: Nat Med. 2009 Aug;15(8):866-70
references.pmid: 19525964
references.citation: Science. 2009 Oct 9;326(5950):285-9
references.pmid: 19729618
references.citation: Science. 2010 Aug 13;329(5993):856-61
references.pmid: 20616233
references.citation: J Virol. 2010 Oct;84(20):10510-21
references.pmid: 20686044
references.citation: J Virol. 2010 Oct;84(20):10690-9
references.pmid: 20702629
references.citation: J Virol. 2011 May;85(10):4828-40
references.pmid: 21389135
references.citation: Nature. 2011 Sep 22;477(7365):466-70
references.pmid: 21849977
references.citation: Science. 2011 Nov 25;334(6059):1097-103
references.pmid: 21998254
references.citation: Nat Med. 2000 Feb;6(2):207-10
references.pmid: 10655111
references.citation: Science. 2003 Jun 27;300(5628):2065-71
references.pmid: 12829775
references.citation: Nature. 2011 Dec 15;480(7377):336-43
references.pmid: 22113616
references.citation: J Virol. 2012 Apr;86(8):4394-403
references.pmid: 22345481
references.citation: Cell Host Microbe. 2012 Oct 18;12(4):396-407
references.pmid: 23084910
references.citation: Nat Med. 2012 Nov;18(11):1688-92
references.pmid: 23086475
references.citation: Proc Natl Acad Sci U S A. 2012 Nov 13;109(46):18921-5
references.pmid: 23100539
references.citation: Nature. 2012 Nov 15;491(7424):406-12
references.pmid: 23151583
references.citation: Proc Natl Acad Sci U S A. 2012 Nov 20;109(47):E3268-77
references.pmid: 23115339
references.citation: Nature. 2012 Dec 6;492(7427):118-22
references.pmid: 23103874
references.citation: PLoS Pathog. 2013 Feb;9(2):e1003173
references.pmid: 23468623
references.citation: PLoS Pathog. 2013;9(5):e1003342
references.pmid: 23658524
references.citation: Nat Struct Mol Biol. 2013 Jul;20(7):796-803
references.pmid: 23708606
references.citation: Nature. 2013 Nov 14;503(7475):224-8
references.pmid: 24172905