title: Expression of H5 hemagglutinin vaccine antigen in common duckweed (Lemna minor) protects against H5N1 high pathogenicity avian influenza virus challenge in immunized chickens.
abstract: A synthetic hemagglutinin (HA) gene from the highly pathogenic avian influenza (HPAI) virus A/chicken/Indonesia/7/2003 (H5N1) (Indo/03) was expressed in aquatic plant Lemna minor (rLemna-HA). In Experiment 1, efficacy of rLemna-HA was tested on birds immunized with 0.2μg or 2.3 μg HA and challenged with 10(6) mean chicken embryo infectious doses (EID50) of homologous virus strain. Both dosages of rLemna-HA conferred clinical protection and dramatically reduced viral shedding. Almost all the birds immunized with either dosage of rLemna-HA elicited HA antibody titers against Indo/03 antigen, suggesting an association between levels of anti-Indo/03 antibodies and protection. In Experiment 2, efficacy of rLemna-HA was tested on birds immunized with 0.9 μg or 2.2 μg HA and challenged with 10(6) EID50 of heterologous H5N1 virus strains A/chicken/Vietnam/NCVD-421/2010 (VN/10) or A/chicken/West Java/PWT-WIJ/2006 (PWT/06). Birds challenged with VN/10 exhibited 100% survival regardless of immunization dosage, while birds challenged with PWT/06 had 50% and 30% mortality at 0.9 μg HA and 2.2 μg HA, respectively. For each challenge virus, viral shedding titers from 2.2 μg HA vaccinated birds were significantly lower than those from 0.9μg HA vaccinated birds, and titers from both immunized groups were in turn significantly lower than those from sham vaccinated birds. Even if immunized birds elicited HA titers against the vaccine antigen Indo/03, only the groups challenged with VN/10 developed humoral immunity against the challenge antigen. None (rLemna-HA 0.9 μg HA) and 40% (rLemna-HA 2.2 μg HA) of the immunized birds challenged with PWT/06 elicited pre-challenge antibody titers, respectively. In conclusion, Lemna-expressed HA demonstrated complete protective immunity against homologous challenge and suboptimal protection against heterologous challenge, the latter being similar to results from inactivated whole virus vaccines. Transgenic duckweed-derived HA could be a good alternative for producing high quality antigen for an injectable vaccine against H5N1 HPAI viruses.
authors.affiliation: Southeast Poultry Research Laboratory, USDA-ARS, 934 College Station Road, Athens, GA 30605, USA. Electronic address: kateri.bertran@ars.usda.gov.
authors.forename: Kateri
authors.initials: K
authors.lastname: Bertran
authors.affiliation: Southeast Poultry Research Laboratory, USDA-ARS, 934 College Station Road, Athens, GA 30605, USA. Electronic address: colleen.thomas@fda.hhs.gov.
authors.forename: Colleen
authors.initials: C
authors.lastname: Thomas
authors.affiliation: Merial Limited, R&D, 115 Trans Tech Drive, Athens, GA 30601, USA. Electronic address: Xuan.Guo@merial.com.
authors.forename: Xuan
authors.initials: X
authors.lastname: Guo
authors.affiliation: Merial S.A.S., R&D, 69007 Lyon, France. Electronic address: Michel.bublot@merial.com.
authors.forename: Michel
authors.initials: M
authors.lastname: Bublot
authors.affiliation: Merial Select, Inc., R&D, 1168 Airport Parkway, Gainesville, GA 30501, USA. Electronic address: Nikki.Pritchard@merial.com.
authors.forename: Nikki
authors.initials: N
authors.lastname: Pritchard
authors.affiliation: Biolex Therapeutics, 158 Credle Street, Pittsboro, NC 27312, USA. Electronic address: reganj75@gmail.com.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Regan
authors.affiliation: Biolex Therapeutics, 158 Credle Street, Pittsboro, NC 27312, USA. Electronic address: kvcx@novozymes.com.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Cox
authors.affiliation: Biolex Therapeutics, 158 Credle Street, Pittsboro, NC 27312, USA. Electronic address: jrgazman@gmail.com.
authors.forename: John R
authors.initials: JR
authors.lastname: Gasdaska
authors.affiliation: Biolex Therapeutics, 158 Credle Street, Pittsboro, NC 27312, USA. Electronic address: lfdickey@gmail.com.
authors.forename: Lynn F
authors.initials: LF
authors.lastname: Dickey
authors.affiliation: Southeast Poultry Research Laboratory, USDA-ARS, 934 College Station Road, Athens, GA 30605, USA. Electronic address: darrell.kapczynski@ars.usda.gov.
authors.forename: Darrell R
authors.initials: DR
authors.lastname: Kapczynski
authors.affiliation: Southeast Poultry Research Laboratory, USDA-ARS, 934 College Station Road, Athens, GA 30605, USA. Electronic address: david.swayne@ars.usda.gov.
authors.forename: David E
authors.initials: DE
authors.lastname: Swayne
mesh_terms: D000818:Animals; D029064:Araceae / Q000235:genetics / Q000378:metabolism*; D002645:Chickens; D015870:Gene Expression; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000378:metabolism*; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D005585:Influenza in Birds / Q000517:prevention & control*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D016019:Survival Analysis; D016896:Treatment Outcome; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D017201:Virus Shedding
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D014614:Vaccines, Synthetic; C109963:hemagglutinin, avian influenza A virus
keywords: Chickens; H5N1 high pathogenicity avian influenza; Hemagglutinin; Plant-derived vaccine