title: Rice endosperm is cost-effective for the production of recombinant griffithsin with potent activity against HIV.
abstract: Protein microbicides containing neutralizing antibodies and antiviral lectins may help to reduce the rate of infection with human immunodeficiency virus (HIV) if it is possible to manufacture the components in large quantities at a cost affordable in HIV-endemic regions such as sub-Saharan Africa. We expressed the antiviral lectin griffithsin (GRFT), which shows potent neutralizing activity against HIV, in the endosperm of transgenic rice plants (Oryza sativa), to determine whether rice can be used to produce inexpensive GRFT as a microbicide ingredient. The yield of (OS) GRFT in the best-performing plants was 223 μg/g dry seed weight. We also established a one-step purification protocol, achieving a recovery of 74% and a purity of 80%, which potentially could be developed into a larger-scale process to facilitate inexpensive downstream processing. (OS) GRFT bound to HIV glycans with similar efficiency to GRFT produced in Escherichia coli. Whole-cell assays using purified (OS) GRFT and infectivity assays using crude extracts of transgenic rice endosperm confirmed that both crude and pure (OS) GRFT showed potent activity against HIV and the crude extracts were not toxic towards human cell lines, suggesting they could be administered as a microbicide with only minimal processing. A freedom-to-operate analysis confirmed that GRFT produced in rice is suitable for commercial development, and an economic evaluation suggested that 1.8 kg/ha of pure GRFT could be produced from rice seeds. Our data therefore indicate that rice could be developed as an inexpensive production platform for GRFT as a microbicide component.
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: Evangelia
authors.identifier: 0000-0002-9818-4404
authors.initials: E
authors.lastname: Vamvaka
authors.affiliation: Department for Applied Genetics and Cell Biology, Molecular Plant Physiology and Crop Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria.
authors.forename: Elsa
authors.initials: E
authors.lastname: Arcalis
authors.affiliation: Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, NIH, Frederick, MD, USA.
authors.forename: Koreen
authors.initials: K
authors.lastname: Ramessar
authors.affiliation: Department of Medicine, Imperial College London, Norfolk Place, London, UK.
authors.forename: Abbey
authors.initials: A
authors.lastname: Evans
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: Barry R
authors.initials: BR
authors.lastname: O'Keefe
authors.affiliation: Department of Medicine, Imperial College London, Norfolk Place, London, UK.
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Shattock
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: Vicente
authors.initials: V
authors.lastname: Medina
authors.affiliation: Department for Applied Genetics and Cell Biology, Molecular Plant Physiology and Crop Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria.
authors.forename: Eva
authors.initials: E
authors.lastname: Stöger
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: Paul
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.
authors.forename: Teresa
authors.initials: T
authors.lastname: Capell
mesh_terms: D019380:Anti-HIV Agents / Q000302:isolation & purification / Q000378:metabolism*; D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D056625:Endosperm / Q000235:genetics* / Q000378:metabolism; D006678:HIV / Q000187:drug effects*; D006367:HeLa Cells; D006801:Humans; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D037121:Plant Lectins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D030821:Plants, Genetically Modified / Q000378:metabolism; D017510:Protein Folding
chemical_list: D019380:Anti-HIV Agents; D000890:Anti-Infective Agents; D037121:Plant Lectins; C499654:griffithsin protein, Griffithsia
keywords: HIV; endosperm; griffithsin; lectin; microbicides; rice