GPI-anchored single chain Fv--an effective way to capture transiently-exposed neutralization epitopes on HIV-1 envelope spike.

Michael Wen (1) , Reetakshi Arora (2) , Huiqiang Wang (1) , Lihong Liu (1) , Jason T Kimata (2) , Paul Zhou (1)

1 LMVI - Key Laboratory of Molecular Virology & Immunology
2 Department of Molecular Virology and Microbiology

BACKGROUND: Identification of broad neutralization epitopes in HIV-1 envelope spikes is paramount for HIV-1 vaccine development. A few broad neutralization epitopes identified so far are present on the surface of native HIV-1 envelope spikes whose recognition by antibodies does not depend on conformational changes of the envelope spikes. However, HIV-1 envelope spikes also contain transiently-exposed neutralization epitopes, which are more difficult to identify. RESULTS: In this study, we constructed single chain Fvs (scFvs) derived from seven human monoclonal antibodies and genetically linked them with or without a glycosyl-phosphatidylinositol (GPI) attachment signal. We show that with a GPI attachment signal the scFvs are targeted to lipid rafts of plasma membranes. In addition, we demonstrate that four of the GPI-anchored scFvs, but not their secreted counterparts, neutralize HIV-1 with various degrees of breadth and potency. Among them, GPI-anchored scFv (X5) exhibits extremely potent and broad neutralization activity against multiple clades of HIV-1 strains tested. Moreover, we show that GPI-anchored scFv (4E10) also exhibited more potent neutralization activity than its secretory counterpart. Finally, we demonstrate that expression of GPI-anchored scFv (X5) in the lipid raft of plasma membrane of human CD4+ T cells confers long-term resistance to HIV-1 infection, HIV-1 envelope-mediated cell-cell fusion, and the infection of HIV-1 captured and transferred by human DCs. CONCLUSIONS: Thus GPI-anchored scFv could be used as a general and effective way to identify antibodies that react with transiently-exposed neutralization epitopes in envelope proteins of HIV-1 and other enveloped viruses. The GPI-anchored scFv (X5), because of its breadth and potency, should have a great potential to be developed into anti-viral agent for HIV-1 prevention and therapy.

Domaines: Microbiologie et Parasitologie

Michael Wen, Reetakshi Arora, Huiqiang Wang, Lihong Liu, Jason T Kimata, et al.. GPI-anchored single chain Fv--an effective way to capture transiently-exposed neutralization epitopes on HIV-1 envelope spike.. Retrovirology, 2010, 7, pp.79. ⟨10.1186/1742-4690-7-79⟩. ⟨pasteur-00624954⟩