title: Biochemical and immunological characterization of the plant-derived candidate human immunodeficiency virus type 1 mucosal vaccine CTB-MPR.
abstract: Plants are potentially the most economical platforms for the large-scale production of recombinant proteins. Thus, plant-based expression of subunit human immunodeficiency virus type 1 (HIV-1) vaccines provides an opportunity for their global use against the acquired immunodeficiency syndrome pandemic. CTB-MPR(649-684)[CTB, cholera toxin B subunit; MPR, membrane proximal (ectodomain) region of gp41] is an HIV-1 vaccine candidate that has been shown previously to induce antibodies that block a pathway of HIV-1 mucosal transmission. In this article, the molecular characterization of CTB-MPR(649-684) expressed in transgenic Nicotiana benthamiana plants is reported. Virtually all of the CTB-MPR(649-684) proteins expressed in the selected line were shown to have assembled into pentameric, GM1 ganglioside-binding complexes. Detailed biochemical analyses on the purified protein revealed that it was N-glycosylated, predominantly with high-mannose-type glycans (more than 75%), as predicted from a consensus asparagine-X-serine/threonine (Asn-X-Ser/Thr) N-glycosylation sequon on the CTB domain and an endoplasmic reticulum retention signal attached at the C-terminus of the fusion protein. Despite this modification, the plant-expressed protein retained the nanomolar affinity to GM1 ganglioside and the critical antigenicity of the MPR(649-684) moiety. Furthermore, the protein induced mucosal and serum anti-MPR(649-684) antibodies in mice after mucosal prime-systemic boost immunization. Our data indicate that plant-based expression can be a viable alternative for the production of this subunit HIV-1 vaccine candidate.
authors.affiliation: Center for Infectious Diseases and Vaccinology at the Biodesign Institute and School of Life Sciences, PO Box 874501, Arizona State University, Tempe, AZ 85287-4501, USA.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Matoba
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kajiura
authors.forename: Irene
authors.initials: I
authors.lastname: Cherni
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Doran
authors.forename: Morgane
authors.initials: M
authors.lastname: Bomsel
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Fujiyama
authors.forename: Tsafrir S
authors.initials: TS
authors.lastname: Mor
mesh_terms: D016915:AIDS Vaccines / Q000096:biosynthesis / Q000276:immunology*; D000818:Animals; D002772:Cholera Toxin / Q000235:genetics / Q000276:immunology; D005260:Female; D006031:Glycosylation; D015483:HIV Antibodies / Q000097:blood; D015700:HIV Envelope Protein gp41 / Q000235:genetics / Q000276:immunology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D018928:Immunity, Mucosal; D051379:Mice; D008807:Mice, Inbred BALB C; D030821:Plants, Genetically Modified / Q000235:genetics / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology*; D014026:Nicotiana / Q000235:genetics / Q000276:immunology*; D022223:Vaccines, Subunit / Q000276:immunology
chemical_list: D016915:AIDS Vaccines; D015483:HIV Antibodies; D015700:HIV Envelope Protein gp41; D011993:Recombinant Fusion Proteins; D022223:Vaccines, Subunit; D002772:Cholera Toxin