title: HIV-1 neutralization profile and plant-based recombinant expression of actinohivin, an Env glycan-specific lectin devoid of T-cell mitogenic activity.
abstract: The development of a topical microbicide blocking the sexual transmission of HIV-1 is urgently needed to control the global HIV/AIDS pandemic. The actinomycete-derived lectin actinohivin (AH) is highly specific to a cluster of high-mannose-type glycans uniquely found on the viral envelope (Env). Here, we evaluated AH's candidacy toward a microbicide in terms of in vitro anti-HIV-1 activity, potential side effects, and recombinant producibility. Two validated assay systems based on human peripheral blood mononuclear cell (hPBMC) infection with primary isolates and TZM-bl cell infection with Env-pseudotyped viruses were employed to characterize AH's anti-HIV-1 activity. In hPMBCs, AH exhibited nanomolar neutralizing activity against primary viruses with diverse cellular tropisms, but did not cause mitogenicity or cytotoxicity that are often associated with other anti-HIV lectins. In the TZM-bl-based assay, AH showed broad anti-HIV-1 activity against clinically-relevant, mucosally transmitting strains of clades B and C. By contrast, clade A viruses showed strong resistance to AH. Correlation analysis suggested that HIV-1's AH susceptibility is significantly linked to the N-glycans at the Env C2 and V4 regions. For recombinant (r)AH expression, we evaluated a tobacco mosaic virus-based system in Nicotiana benthamiana plants as a means to facilitate molecular engineering and cost-effective mass production. Biochemical analysis and an Env-mediated syncytium formation assay demonstrated high-level expression of functional rAH within six days. Taken together, our study revealed AH's cross-clade anti-HIV-1 activity, apparent lack of side effects common to lectins, and robust producibility using plant biotechnology. These findings justify further efforts to develop rAH toward a candidate HIV-1 microbicide.
authors.affiliation: Owensboro Cancer Research Program, Owensboro, Kentucky, United States of America. n.matoba@louisville.edu
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Matoba
authors.forename: Adam S
authors.initials: AS
authors.lastname: Husk
authors.forename: Brian W
authors.initials: BW
authors.lastname: Barnett
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Pickel
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Arntzen
authors.forename: David C
authors.initials: DC
authors.lastname: Montefiori
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Tanno
authors.forename: Satoshi
authors.initials: S
authors.lastname: Omura
authors.forename: Huyen
authors.initials: H
authors.lastname: Cao
authors.forename: Jason P
authors.initials: JP
authors.lastname: Mooney
authors.forename: Carl V
authors.initials: CV
authors.lastname: Hanson
authors.forename: Haruo
authors.initials: H
authors.lastname: Tanaka
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D015497:HIV-1 / Q000276:immunology*; D006367:HeLa Cells; D006801:Humans; D008934:Mitogens / Q000494:pharmacology; D009500:Neutralization Tests; D011994:Recombinant Proteins / Q000235:genetics / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects*; D014026:Nicotiana / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D008934:Mitogens; D011994:Recombinant Proteins; C424136:actinohivin protein, actinomycete