We have previously shown that neutrophils in the presence of GM-CSF, IL-3 and IFN-γ fully activate allergen-specific CD4+ T-cells resulting in their proliferation and the release of cytokines, and detected HLA-DR+ neutrophils in allergic late phase reactions in vivo. These findings tempted us to assess whether activated allergen-specific CD4+ T-cells in a kind of feedback mechanisms may suppress or promote the antigen-presenting activity of neutrophils. In the present study, we investigated the effect varying doses of various different T cell-derived cytokines on the expression of HLA-DR and costimulatory molecules, respectively, as well as allergen-uptake and presentation by neutrophils. We identified GM-CSF as most relevant cytokine for enhancing their antigen-presenting activity. Moreover, we found that the immunosuppressive cytokine IL-10 inhibits allergen-uptake by neutrophils. However, this effect was overruled by the other cytokines. In summary, our results indicate that activated allergen-specific Th cells create a cytokine environment which enhances the life-span of neutrophils and transforms them into antigen-presenting cells.
T cell-derived cytokines enhance the antigen-presenting capacity of human neutrophils.