title: Development of a DNA vaccine expressing a secreted HIV-1 gp41 ectodomain that includes the membrane-proximal external region.
abstract: A limited number of sites on the HIV-1 Envelope protein are vulnerable to broadly neutralizing antibodies (bnAbs). One of these sites, the membrane proximal external region (MPER), is located at the C-terminus of the gp41 ectodomain (gp41ecto). This highly conserved sequence is bound by several well-characterized bnAbs. Efforts to produce a gp41 immunogen are in part hampered by the MPER's hydrophobicity and propensity to induce aggregation. We sought to produce a DNA vaccine expressing a gp41ectothat is both secreted from mammalian cells and maintains binding by bnAbs to the MPER. Through in silico analysis, we predicted regions of gp41ectothat could induce aggregation and possibly hinder secretion. We generated deletion mutants of gp41ectoand tested their ability to be secreted by mammalian cells. Upon deletion of regions in either the fusion peptide (FP) or MPER, secretion of the gp41ectoincreased. In an effort to both augment secretion and maintain binding by bnAbs, we developed constructs with the FP deletion and introduced point mutations in the MPER. Two constructs (gp41 ΔFP and gp41 ΔFP+I682E) maintained binding by gp41 MPER-specific bnAbs (4E10, Z13e1 and 10E8). These were evaluated as DNA vaccines in a mouse model. Both vaccines proved to be immunogenic and appeared to elicit some MPER-specific antibodies that bound gp41 ectodomain-derived proteins but not short peptides spanning the MPER. No neutralizing capacity was detected against a clade C virus containing a homologous MPER.
authors.affiliation: Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada; Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Luca
authors.initials: L
authors.lastname: Melnychuk
authors.affiliation: Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada; Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Lara
authors.initials: L
authors.lastname: Ajamian
authors.affiliation: Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Patrick
authors.initials: P
authors.lastname: Jean-Pierre
authors.affiliation: Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada; Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Jiaming
authors.initials: J
authors.lastname: Liang
authors.affiliation: Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Romina
authors.initials: R
authors.lastname: Gheorghe
authors.affiliation: Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada; Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wainberg
authors.affiliation: Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada; Division of Infectious Diseases, Department of Medicine, Jewish General Hospital, Montréal, Québec, Canada. Electronic address: gerasimos.zaharatos@mcgill.ca.
authors.forename: Gerasimos J
authors.initials: GJ
authors.lastname: Zaharatos
mesh_terms: D016915:AIDS Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D000818:Animals; D005260:Female; D015483:HIV Antibodies / Q000097:blood; D015700:HIV Envelope Protein gp41 / Q000235:genetics / Q000276:immunology*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology*; D006803:Human Development; D006801:Humans; D008807:Mice, Inbred BALB C; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
chemical_list: D016915:AIDS Vaccines; D015483:HIV Antibodies; D015700:HIV Envelope Protein gp41; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic; C514787:gp41 protein, Human immunodeficiency virus 1
keywords: Broadly neutralizing antibodies; DNA vaccine; HIV-1; Membrane-proximal external region; gp41