Augmented Phl p 5-specific Th2 response after exposure of Dendritic Cells to allergen in complex with specific IgE compared to IgG1 and IgG4

In this study we have elucidated the effects of allergen-specific antibodies on human DCs and T-cells. Monocyte-derived DCs from allergic patients were exposed to Phlp 5 alone or in complex with Phlp 5-specific human IgG1, IgG4 or IgE and further co-cultured with autologous memory CD4+ T-cells. We demonstrate that DCs treated with Phlp 5/IgE-complexes secrete higher levels of IL-1a, IL-6, VEGF and MCP-3 compared to Phlp 5 alone. Furthermore, we show that the ability of DCs to present allergen to memory CD4+ T-cells and induce a Th2 cytokine profile is significantly augmented when the uptake is mediated by specific IgE antibodies, whereas IgG1 and IgG4 have no such effect. The differences in cytokine profiles depending on the antibody subtype could partly explain the ability of allergic individuals to amplify allergen-specific immune response and could thus be involved in the etiology of allergic responses.