title: Immunization with plasmid DNA encoding a truncated, secreted form of the bovine viral diarrhea virus E2 protein elicits strong humoral and cellular immune responses.
abstract: The major protective antigen of bovine viral diarrhea virus (BVDV), the E2 protein, is cell-associated and not expressed on the cell surface. In this study we evaluated a DNA vaccine encoding various secreted versions of E2. In vitro analysis demonstrated that deletion of the transmembrane anchor and addition of the signal sequence of bovine herpesvirus-1 (BHV-1) (gDsDeltaE2) resulted in efficient secretion of E2 into the culture medium. In contrast, full-length E2, either without or with gDs (gDsE2), as well as truncated E2 without gDs (DeltaE2), remained entirely cell-associated. Mice immunized with plasmid encoding gDsDeltaE2 developed significantly higher IgG and virus neutralizing antibody titres compared to animals vaccinated with plasmid encoding E2, DeltaE2 or gDsE2. To optimize secretion of E2, the efficiency of gDs was compared with that of the tissue plasminogen activator signal (tPAs) sequence. In addition, the effect of the plasmid backbone was assessed by comparing two vectors. Four plasmids, pMASIA-gDsDeltaE2, pMASIA-tPAsDeltaE2, pSLKIA-gDsDeltaE2 and pSLKIA-tPAsDeltaE2, were constructed and administered intradermally to mice. The mice immunized with pMASIA-tPAsDeltaE2 developed the strongest and most balanced immune responses. Vaccination of cattle confirmed that pMASIA-tPAsDeltaE2 elicited both strong humoral and cellular immune responses and thus could be a candidate DNA vaccine against BVDV.
authors.affiliation: Vaccine and Infectious Disease Organization, University of Saskatchewan, Sask., Canada S7N 5E3.
authors.forename: Rong
authors.initials: R
authors.lastname: Liang
authors.forename: Jan V
authors.initials: JV
authors.lastname: van den Hurk
authors.forename: Chunfu
authors.initials: C
authors.lastname: Zheng
authors.forename: Hong
authors.initials: H
authors.lastname: Yu
authors.forename: Reno A
authors.initials: RA
authors.lastname: Pontarollo
authors.forename: Lorne A
authors.initials: LA
authors.lastname: Babiuk
authors.forename: Sylvia
authors.initials: S
authors.lastname: van Drunen Littel-van den Hurk
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000276:immunology*; D015153:Blotting, Western; D019556:COS Cells; D002417:Cattle; D049109:Cell Proliferation; D002522:Chlorocebus aethiops; D017931:DNA Primers / Q000276:immunology; D030241:Diarrhea Virus 1, Bovine Viral / Q000235:genetics / Q000276:immunology; D030242:Diarrhea Virus 2, Bovine Viral / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D007242:Herpesvirus 1, Bovine / Q000276:immunology; D007111:Immunity, Cellular / Q000276:immunology*; D007114:Immunization; D007371:Interferon-gamma; D051379:Mice; D009500:Neutralization Tests; D010957:Plasmids / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D010959:Tissue Plasminogen Activator / Q000276:immunology; D014162:Transfection; D019444:Vaccines, DNA / Q000276:immunology*; D014764:Viral Proteins / Q000276:immunology*
chemical_list: D017931:DNA Primers; D019444:Vaccines, DNA; D014764:Viral Proteins; D007371:Interferon-gamma; D010959:Tissue Plasminogen Activator