title: The effect of helper epitopes and cellular localization of an antigen on the outcome of gene gun DNA immunization.
abstract: In DNA vaccination, CD4(+) T-cell help can be enhanced by fusion of a gene encoding an immunization protein with a foreign gene or its part providing T(h) epitopes. To study the effect of helper epitope localization in a protein molecule, the influence of the vicinity of the helper epitope, and the impact of chimeric protein cellular localization, we fused the helper epitope p30 from tetanus toxin (TT, aa 947-967) with the N- or C-terminus of the mutated E7 oncoprotein (E7GGG) of human papillomavirus type 16, enlarged the p30 epitope with the flanking residues containing potential protease-sensitive sites and altered the cellular localization of the fusion constructs by signal sequences. The p30 epitope enhanced the E7-specific response, but only in constructs without added signal sequences. After localization of the fusion proteins into the endoplasmic reticulum and endo/lysosomal compartment, the TT-specific T(h)2 response was increased. The synthetic Pan DR epitope (PADRE) induced a stronger E7-specific response than the p30 epitope and its stimulatory effect was not limited to nuclear/cytoplasmic localization of the E7 antigen. These results suggest that in the optimization of immune responses by adding helper epitopes to DNA vaccines delivered by the gene gun, the cellular localization of the antigen needs to be taken into account.
authors.affiliation: Department of Experimental Virology, Institute of Hematology and Blood Transfusion, Prague 2, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Smahel
authors.affiliation: Department of Experimental Virology, Institute of Hematology and Blood Transfusion, Prague 2, Czech Republic.
authors.forename: I
authors.initials: I
authors.lastname: Polakova
authors.affiliation: Department of Experimental Virology, Institute of Hematology and Blood Transfusion, Prague 2, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Duskova
authors.affiliation: Department of Experimental Virology, Institute of Hematology and Blood Transfusion, Prague 2, Czech Republic.
authors.forename: V
authors.initials: V
authors.lastname: Ludvikova
authors.affiliation: Department of Experimental Virology, Institute of Hematology and Blood Transfusion, Prague 2, Czech Republic.
authors.forename: I
authors.initials: I
authors.lastname: Kastankova
mesh_terms: D000818:Animals; D019470:Biolistics / Q000379:methods*; D045744:Cell Line, Tumor; D016207:Cytokines / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000276:immunology* / Q000378:metabolism; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D017780:Malaria Vaccines / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D041681:NIH 3T3 Cells; D050725:Papillomavirus E7 Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D010446:Peptide Fragments / Q000235:genetics* / Q000494:pharmacology; D010957:Plasmids / Q000008:administration & dosage; D011993:Recombinant Fusion Proteins / Q000378:metabolism / Q000494:pharmacology; D013744:Tetanus Toxin / Q000235:genetics* / Q000494:pharmacology; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D016207:Cytokines; D017780:Malaria Vaccines; C091828:P30 tetanus toxin peptide; C401223:PADRE 45; D050725:Papillomavirus E7 Proteins; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D013744:Tetanus Toxin; D019444:Vaccines, DNA; C059731:oncogene protein E7, Human papillomavirus type 16