title: Structural integrity of the antigen is a determinant for the induction of T-helper type-1 immunity in mice by gene gun vaccines against E. coli beta-galactosidase.
abstract: The type of immune response is critical for successful protection and typically determined by pathogen-associated danger molecules. In contrast, protein antigens are usually regarded as passive target structures. Here, we provide evidence that the structure of the antigen can profoundly influence the type of response that is elicited under else identical conditions. In mice, gene gun vaccines induce predominantly Th2-biased immune reactions against most antigens. One exception is E. coli beta-galactosidase (βGal) that induces a balanced Th1/Th2 response. Because both, the delivered material (plasmid DNA-coated gold particles) as well as the procedure (biolistic delivery to the skin surface) is the same as for other antigens we hypothesized that Th1 induction could be a function of βGal protein expressed in transfected cells. To test this we examined gene gun vaccines encoding structural or functional variants of the antigen. Employing a series of gene gun vaccines encoding individual structural domains of βGal, we found that neither of them induced IgG2a antibodies. Even disruption of the homo-tetramer association of the native protein by deletion of a few N-terminal amino acids was sufficient to abrogate IgG2a production. However, enzymatically inactive βGal with only one point mutation in the catalytic center retained the ability to induce Th1 reactions. Thus, structural but not functional integrity of the antigen must be retained for Th1 induction. βGal is not a Th1 adjuvant in the classical sense because neither were βGal-transgenic ROSA26 mice particularly Th1-biased nor did co-administration of a βGal-encoding plasmid induce IgG2a against other antigens. Despite this, gene gun vaccines elicited Th1 reactions to antigens fused to the open reading frame of βGal. We interpret these findings as evidence that different skin-borne antigens may be differentially handled by the immune system and that the three-dimensional structure of an antigen is an important determinant for this.
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Tekalign
authors.initials: T
authors.lastname: Deressa
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Angelika
authors.initials: A
authors.lastname: Stoecklinger
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Wallner
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Himly
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kofler
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Katrina
authors.initials: K
authors.lastname: Hainz
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Hans
authors.initials: H
authors.lastname: Brandstetter
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Josef
authors.initials: J
authors.lastname: Thalhamer
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Hammerl
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D019470:Biolistics / Q000379:methods; D002460:Cell Line; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D005260:Female; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D051379:Mice; D054730:Protein Interaction Domains and Motifs / Q000276:immunology; D055503:Protein Multimerization / Q000276:immunology; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology*; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*; D001616:beta-Galactosidase / Q000737:chemistry / Q000235:genetics / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D029968:Escherichia coli Proteins; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D019444:Vaccines, DNA; D001616:beta-Galactosidase