title: Cyanovirin-N produced in rice endosperm offers effective pre-exposure prophylaxis against HIV-1BaL infection in vitro.
abstract: Cyanovirin-N produced in rice endosperm provides efficient pre-exposure prophylaxis against HIV-1 BaL infection in vitro. Cyanovirin-N (CV-N) is a lectin with potent antiviral activity that has been proposed as a component of microbicides for the prevention of infection with Human immunodeficiency virus (HIV). The production of protein-based microbicide components requires a platform that is sufficiently economical and scalable to meet the demands of the large at-risk population, particularly in resource poor developing countries. We, therefore, expressed CV-N in rice endosperm, because the dried seed is ideal for storage and transport and crude extracts could be prepared locally and used as a microbicide component without further purification. We found that crude extracts from rice seeds expressing up to 10 µg CV-N per gram dry seed weight showed dose-dependent gp120 binding activity, confirming that the protein was soluble, correctly folded and active. The recombinant lectin ((OS)CV-N) reduced the infectivity of HIV-1BaL (an R5 virus strain representing the majority of transmitted infections) by ~90 % but showed only weak neutralization activity against HIV-1RF (representative of X4 virus, rarely associated with transmission), suggesting it would be highly effective for pre-exposure prophylaxis against the vast majority of transmitted strains. Crude extracts expressing (OS)CV-N showed no toxicity towards human cells at working dilutions indicating that microbicide components produced in rice endosperm are safe for direct application as topical microbicides in humans.
authors.affiliation: Department of Plant Production and Forestry Science, School of Agrifood and Forestry Science and Engineering (ETSEA), University of Lleida-Agrotecnio Center, Lleida, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Vamvaka
authors.affiliation: Department of Medicine, Imperial College London, Norfolk Place, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Evans
authors.affiliation: Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, USA.
authors.forename: K
authors.initials: K
authors.lastname: Ramessar
authors.affiliation: Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, USA.|Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, MD, USA.
authors.forename: L R H
authors.initials: LR
authors.lastname: Krumpe
authors.affiliation: Department of Medicine, Imperial College London, Norfolk Place, London, UK.
authors.forename: R J
authors.initials: RJ
authors.lastname: Shattock
authors.affiliation: Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, USA.|Natural Products Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, NIH, Frederick, MD, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: O'Keefe
authors.affiliation: Department of Plant Production and Forestry Science, School of Agrifood and Forestry Science and Engineering (ETSEA), University of Lleida-Agrotecnio Center, Lleida, Spain.|Catalan Institute for Research and Advanced Studies (ICREA), Barcelona, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Christou
authors.affiliation: Department of Plant Production and Forestry Science, School of Agrifood and Forestry Science and Engineering (ETSEA), University of Lleida-Agrotecnio Center, Lleida, Spain. teresa.capell@pvcf.udl.cat.
authors.forename: T
authors.initials: T
authors.lastname: Capell
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism / Q000627:therapeutic use*; D002352:Carrier Proteins / Q000378:metabolism / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D056625:Endosperm / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D015658:HIV Infections / Q000517:prevention & control*; D015497:HIV-1 / Q000187:drug effects*; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D009500:Neutralization Tests; D012275:Oryza / Q000378:metabolism*; D008517:Phytotherapy / Q000379:methods; D010936:Plant Extracts / Q000627:therapeutic use*; D030821:Plants, Genetically Modified; D065129:Pre-Exposure Prophylaxis / Q000379:methods*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D010936:Plant Extracts; C107733:cyanovirin N
keywords: Anti-HIV; Cyanovirin-N; Endosperm; Microbicide; Rice crude extract