title: Differential immunogenicity of a DNA vaccine containing the Streptococcus mutans wall-associated protein A gene versus that containing a truncated derivative antigen A lacking in the hydrophobic carboxyterminal region.
abstract: Two plasmid DNA constructs were obtained by cloning separately into the eukaryotic expression vector pcDNA3.1/V5-His-TOPO the wall-associated protein A (wapA) gene of Streptococcus mutans GS-5 or its truncated derivative antigen A (agA) gene encoding a known candidate antigen for dental caries vaccine. The immunogenicity of the two constructs, designated pcDNA-wapA and pcDNA-agA, was compared by intranasal immunization of two groups of mice using the cationic DMRIE-C (1,2-dimyristyloxypropyl-3-dimethylhydroxy ethyl ammonium bromide-cholesterol) as an adjuvant. Immunization with pcDNA-wapA or pcDNA- agA resulted in specific salivary IgA and systemic IgG antibodies to the target antigens after two doses given at 3-week intervals. Higher salivary IgA level was observed in the mice immunized with the pcDNA-wapA vaccine compared to those immunized with the pcDNA-agA vaccine. Furthermore, anti-WapA antibody inhibited S. mutans sucrose-dependent adherence suggesting a potential protection against S. mutans colonization of the tooth, while anti-AgA had no significant effect. Indeed, prediction and analysis of protein epitopes showed that WapA contains highly promiscuous MHC-II binding motifs in addition to those found in AgA. Immunodot assay confirmed that WapA bound biotin-labeled dextran, whereas AgA did not. These data indicated that full-length WapA is a better candidate vaccine antigen than the soluble AgA, which is truncated in the hydrophobic membrane and wall-spanning region.
authors.affiliation: Department of Biology, University of South Florida, Tampa, 33620, USA.
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Han
authors.forename: My Lien
authors.initials: ML
authors.lastname: Dao
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000942:Antigens, Bacterial / Q000235:genetics* / Q000276:immunology*; D001422:Bacterial Adhesion / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology*; D001710:Biotin / Q000378:metabolism; D003731:Dental Caries / Q000517:prevention & control*; D003911:Dextrans / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli; D005260:Female; D005802:Genes, MHC Class II / Q000235:genetics; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D008055:Lipids; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000235:genetics; D000644:Quaternary Ammonium Compounds; D012463:Saliva / Q000276:immunology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D003911:Dextrans; D000939:Epitopes; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D008055:Lipids; D000644:Quaternary Ammonium Compounds; D019444:Vaccines, DNA; C081813:wapA protein, Bacillus subtilis; C087276:(3-dimyristyloxypropyl)(dimethyl)(hydroxyethyl)ammonium; D001710:Biotin