A human in vitro allergy model showing allergen specific immune responses using house dust mite or grass pollen allergen

Rationale: In the study described, a human in vitro allergy model was established providing an alternative method to animal use investigating allergic immune responses. The model should be able to show the influence of cellular or drug candidates avoiding animal experiments and show close relation to the human situation. Methods: Antigen-presenting cells were generated from whole blood of healthy or allergic donors. APC were stimulated with house dust mite extract (HDM) or Phlp5 and co-cultured with autologous CD4+lymphocytes in the presence of allergen and or immunomodulatory compounds. Effects on T cell proliferation and cytokine secretion were analyzed by ³H-thymidine incorporation and ELISA or Multiplex analysis. Results: Allergen-pulsed APC induced strong proliferation of the CD4+ lymphocytes. The presence of Immunomodulatory plasmacytoid DC (pDC) in the cocultures inhibited this response by about 50%. Proliferation of HDM-stimulated PBMC was dose-dependently reduced by pDC showing a significant deregulating functionality. Conclusions: Allergen-specific T cell response can reproducibly be measured using the human in vitro allergy model showing regulatory properties of pDC. This model mimics regulatory mechanisms of allergic immune responses and might be applicable for efficacy testing of immunoregulatory cellular therapeutics or biomolecules with greater predictivity for the human situation and avoiding animal experiments.