Vaccination with the recombinant allergen ProDer p 1 complexed with the cationic lipid DiC14-amidine prevents allergic responses to house dust mite.

The present study evaluated the prophylactic potential of ProDer p 1, the recombinant precursor form of the major mite allergen Der p 1, combined with the cationic lipid diC14-amidine in a murine model of house dust mite allergy. Naive mice vaccinated with the amidine/allergen complex developed a Th1-biased immune response characterized by the absence of specific IgE, the production of specific IgG2a, and the presence of IFN-gamma in splenocyte cultures. In contrast, ProDer p 1 adjuvanted with alum induced typical strictly Th2-biased allergic responses with strong IgG1 and IgE titers and IL-5 secretion. Removal of negatively charged sialic acids in ProDer p 1 or increasing the ionic strength reduced the binding of ProDer p 1 to the cationic liposomes and resulted in a decrease of the allergen immunogenicity, suggesting that complexation is required for triggering an optimal immune response. Finally, prophylactic vaccination with ProDer p 1-diC14-amidine reduced drastically the production of specific IgE and airway eosinophilia following subsequent immunization with Der p 1-alum and challenge with aerosolized house dust mite extracts. In conclusion, recombinant ProDer p 1 complexed with diC14-amidine could represent an efficient prophylactic vaccine against house dust mite allergy.