Human T cells that have been conditioned by the proteolytic activity of the major dust mite allergen Der p 1 trigger enhanced immunoglobulin E synthesis by B cells

Summary Background We have previously demonstrated that the proteolytic activity of Der p 1 selectively cleaves human CD25, the 55 kDa α subunit of the IL‐2 receptor. As a result of cleavage of surface CD25, peripheral blood T cells produce less IFN‐γ and more IL‐4, thereby leading to progressive polarization of the T cells towards a Th2 cytokine profile. Therefore, these observations underline the potential role of the proteolytic activity of Der p 1 in creating a microenvironment conducive for IgE synthesis. Objective To study the effect of T cells that have been conditioned by the proteolytic activity of Der p 1 on IgE synthesis by B cells. Methods We have examined this concept in experiments whereby T cells that have been exposed to either proteolytically active or inactive Der p 1 were cocultured with autologous B cells and IgE antibody synthesis was monitored. Results Here we demonstrate for the first time that coculturing T cells that have been in contact with proteolytically active Der p 1 with autologous B cells leads to augmentation of IgE antibody responses. Conclusions The proteolytic activity of Der p 1 conditions human T cells, which then become empowered to trigger enhanced IgE synthesis by B cells.