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.

Immune Reactions against Gene Gun Vaccines Are Differentially Modulated by Distinct Dendritic Cell Subsets in the Skin

“…In mice, GG vaccines usually induce IgG1 as the predominant antibody isotype. In contrast to many other antigens, including OVA, βGal induces also other IgG subtypes [ 19 , 28 ]. Testing serum samples of the mice described in Fig 1 revealed that ablation of langerin + cells caused a dramatic reduction in IgG1 against βGal ( Fig 2A , left panel) and, to a lesser extent, also a decline in IgG2c antibodies ( Fig 2A , right panel).…”

A Gene Gun-mediated Nonviral RNA trans-splicing Strategy for Col7a1 Repair

“…In the literature, this approach is mainly described for biolistic-mediated gene vaccinations to induce antigen-specific immune tolerance. 21,28 In 2011, Xia and colleagues 20 evaluated the localization of the gold particles in the epidermis and upper dermis after gene gun treatment. 20 In our study, the desired accumulation of the gold beads containing the transgene for Col7a1 correction in the BMZ and upper dermis was achieved in wild-type mice using a pressure of 300-400 psi, proving an efficient application into the skin.…”

Enzyme adsorption-induced activity changes: a quantitative study on TiO2 model agglomerates

“…β-gal was produced in house as a highly purified recombinant protein according to protocols previously described in detail [27]. All H 2 O solutions were prepared using water with a resistivity of 18 M Ω cm (Millipore, Milli-Q).…”

“…Na 2 CO 3 (Sigma Aldrich, ACS reagent, ≥99.5%), Na 2 HPO 4 (Sigma Aldrich, ACS Reagent ≥99%), citric acid (Sigma Aldrich, ≥99.5%), o-Nitrophenyl-β-D-galactopyranoside (ONPG, Sigma Aldrich, >99% HPLC), MgCl 2 (Sigma Aldrich, ACS Reagent >99%) and D 2 O (Aldrich, 99 atom% D) were used as received. β-gal was produced in house as a highly purified recombinant protein according to protocols previously described in detail [ 27 ]. All H 2 O solutions were prepared using water with a resistivity of 18 M Ω cm (Millipore, Milli-Q).…”