Volume 4 Supplement 2
Induction of allergen-specific blocking IgG using patch delivered recombinant Bet v 1 in guinea pigs
© Cabauatan et al; licensee BioMed Central Ltd. 2014
Published: 17 March 2014
Allergen-specific immunotherapy (SIT) is the only specific, disease-modifying treatment for allergy and may have long-lasting effects. It is given traditionally in the form of multiple subcutaneous injections which makes the treatment inconvenient. Furthermore, systemic allergen-administration may cause severe side effects. Therefor the development of alternative routes for SIT has been a long-sought goal. The aim of this study was to investigate if epicutaneous application of recombinant birch pollen allergen Bet v 1 (i.e., patch vaccination) can induce systemic allergen-specific IgG responses with protective activity.
Groups of outbred female Dunkin Hartley guinea pigs (GP) (10 animals per group) were immunized subcutaneously with aluminium hydroxide-adsorbed rBet v 1 (5 µg), aluminium hydroxide alone (negative control) or by patch delivery system (PDS) using two doses of rBet v 1 (30 µg or 100 µg per patch) on days 1, 15, 28 and 43. ELISA experiments were performed to measure the development of IgG specific for Bet v 1, Bet v 1-related pollen and food allergens ( i.e., Aln g 1, Cor a 1, Mal d 1) and for unfolded Bet v 1 fragments. Furthermore, guinea pig antibodies were tested in IgE ELISA inhibition experiments with allergic patients' sera to study whether allergen-specific IgG can block allergic patients allergen-specific IgE binding.
Already after 42 days and three s. c. injections of aluminium hydroxide-adsorbed rBet v 1 or three patch test vaccinations with the high dose PDS in combination with LT, a relevant induction of allergen-specific IgG was observed in more than 20% of the outbred animals. More importantly, these antisera inhibited allergic patients' (n=5) IgE binding to Bet v 1. Interestingly, we noted that only vaccination with aluminium hydroxide-adsorbed rBet v 1 induced IgG antibodies against sequential epitopes and cross-reactive IgG antibodies whereas patch vaccination seemed to induce primarily Bet v 1-specific IgG directed against conformational epitopes.
Our results suggest that patch vaccination with recombinant Bet v 1 may be a promising strategy for SIT against birch pollen allergy. This study was supported by grant F4605 of the Austrian Science Fund and a research grant from Biomay AG, Vienna, Austria.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.