Background: The worldwide increasing incidence of allergic diseases requires the development of new, efficient vaccination strategies, the only curative treatment with a long-lasting effect. Current allergen-specific immunotherapy protocols suffer from limited efficacy and a long treatment time.
Methods: We engineered modular antigen translocating (MAT) molecules for intracellular targeting of allergens to the major histocompatibility class-II (MHC-II) presentation pathway to enhance antigen presentation. MAT-fusions were evaluated for their ability to localize intracellularly, to induce proliferation, and for their influence on cytokine patterns in peripheral blood mononuclear cells (PBMCs) cultures.
Results: We show that MAT-allergen fusions are able to rapidly translocate into the cytoplasm of PBMCs, whereas naked recombinant allergens are only marginally taken up. MAT vaccines accumulate intracellularly and induce strong proliferation of PBMC cultures at concentrations 10-100 times lower than the corresponding naked allergens, indicating an enhanced presentation through the MHC-II presentation pathway. In PBMC cultures of allergic donors, MAT vaccines induce a cytokine shift from a T(H)2 to a T(H)1 profile, resulting in a stronger and earlier secretion of INF-gamma and Interleukin (IL)-10, and a decreased secretion of IL-4, IL-5 and IL-2, compared with those induced by the corresponding recombinant allergens.
Conclusion: Modular antigen translocation vaccines induce strong proliferation responses in PBMC cultures at low concentration and induce a T(H)1/T(H)2 shift in the cytokine profile, reflecting those reported to occur in successfully desensitized allergic patients. Therefore, MAT molecules represent promising lead compounds for the development of potent allergy vaccines.