title: Immunization with a dicistronic plasmid expressing a truncated form of bovine herpesvirus-1 glycoprotein D and the amino-terminal subunit of glycoprotein B results in reduced gB-specific immune responses.
abstract: As an approach to create a divalent DNA vaccine, a truncated secreted version of bovine herpesvirus-1 (BHV-1) glycoprotein D (tgD) and the amino-terminal subunit of glycoprotein B (gBb) were expressed from a dicistronic plasmid, designated pSLIAtgD-IRES-gBb. Intradermal immunization of mice with pSLIAtgD-IRES-gBb or a mixture of plasmids encoding tgD (pSLIAtgD) and gBb (pSLIAgBb) by needle injection or gene gun elicited strong tgD-specific immune responses. However, a significant reduction in gBb-specific immune responses was observed upon immunization of mice with pSLIAtgD-IRES-gBb or a mixture of pSLIAtgD and pSLIAgBb in comparison to immunization with pSLIAgBb alone. This reduction in gBb-specific immune responses induced by pSLIAtgD-IRES-gBb was due to production of low amounts of gBb from pSLIAtgD-IRES-gBb, inefficient processing and transport of gBb, and possibly competition for antigen-presenting cells by tgD and gBb. These results indicate that, although divalent plasmids may be used to express different antigens, the efficacy of vaccination with such plasmids may be influenced by the plasmid design and the characteristics of the expressed antigens.
authors.affiliation: Veterinary Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E3, Canada.
authors.forename: Sharmila
authors.initials: S
authors.lastname: Manoj
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; D000914:Antibodies, Viral / Q000032:analysis; D019470:Biolistics; D019556:COS Cells; D005822:Genetic Vectors; D007242:Herpesvirus 1, Bovine / Q000276:immunology*; D022283:Herpesvirus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007114:Immunization; D007371:Interferon-gamma / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D010957:Plasmids; D011994:Recombinant Proteins / Q000276:immunology; D013045:Species Specificity; D020079:Terminal Repeat Sequences; D022223:Vaccines, Subunit; D014764:Viral Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D022283:Herpesvirus Vaccines; D011994:Recombinant Proteins; D022223:Vaccines, Subunit; D014764:Viral Proteins; C046998:bovine herpesvirus type-1 glycoproteins; D007371:Interferon-gamma