title: Potent and broad anti-HIV-1 activity exhibited by a glycosyl-phosphatidylinositol-anchored peptide derived from the CDR H3 of broadly neutralizing antibody PG16.
abstract: PG9 and PG16 are two recently isolated quaternary-specific human monoclonal antibodies that neutralize 70 to 80% of circulating HIV-1 isolates. The crystal structure of PG16 shows that it contains an exceptionally long CDR H3 that forms a unique stable subdomain that towers above the antibody surface to confer fine specificity. To determine whether this unique architecture of CDR H3 itself is sufficient for epitope recognition and neutralization, we cloned CDR H3 subdomains derived from human monoclonal antibodies PG16, PG9, b12, E51, and AVF and genetically linked them to a glycosyl-phosphatidylinositol (GPI) attachment signal. Each fusion gene construct is expressed and targeted to lipid rafts of plasma membranes through a GPI anchor. Moreover, GPI-CDR H3(PG16, PG9, and E51), but not GPI-CDR H3(b12 and AVF), specifically neutralized multiple clades of HIV-1 isolates with a great degree of potency when expressed on the surface of transduced TZM-bl cells. Furthermore, GPI-anchored CDR H3(PG16), but not GPI-anchored CDR H3(AVF), specifically confers resistance to HIV-1 infection when expressed on the surface of transduced human CD4(+) T cells. Finally, the CDR H3 mutations (Y100HF, D100IA, and G7) that were previously shown to compromise the neutralization activity of antibody PG16 also abolished the neutralization activity of GPI-CDR H3(PG16). Thus, we conclude that the CDR H3 subdomain of PG16 neutralizes HIV-1 when targeted to the lipid raft of the plasma membrane of HIV-1-susceptible cells and that GPI-CDR H3 can be an alternative approach for determining whether the CDR H3 of certain antibodies alone can exert epitope recognition and neutralization.
authors.affiliation: Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200025, China.
authors.forename: Lihong
authors.initials: L
authors.lastname: Liu
authors.forename: Michael
authors.initials: M
authors.lastname: Wen
authors.forename: Weiming
authors.initials: W
authors.lastname: Wang
authors.forename: Shumei
authors.initials: S
authors.lastname: Wang
authors.forename: Lifei
authors.initials: L
authors.lastname: Yang
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.forename: Mengran
authors.initials: M
authors.lastname: Qian
authors.forename: Linqi
authors.initials: L
authors.lastname: Zhang
authors.forename: Yiming
authors.initials: Y
authors.lastname: Shao
authors.forename: Jason T
authors.initials: JT
authors.lastname: Kimata
authors.forename: Paul
authors.initials: P
authors.lastname: Zhou
mesh_terms: D057134:Antibodies, Neutralizing / Q000235:genetics / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D002460:Cell Line; D003001:Cloning, Molecular; D015870:Gene Expression; D006020:Glycopeptides / Q000235:genetics / Q000276:immunology*; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D015483:HIV Antibodies / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000276:immunology* / Q000502:physiology; D006801:Humans; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000378:metabolism; D053586:Virus Internalization
chemical_list: D057134:Antibodies, Neutralizing; D006020:Glycopeptides; D017261:Glycosylphosphatidylinositols; D015483:HIV Antibodies; D011993:Recombinant Fusion Proteins