PROTEOLYTIC CLEAVAGE OF CD25, THE ALPHA-SUBUNIT OF THE HUMAN T-CELL INTERLEUKIN-2 RECEPTOR, BY DER-P-1, A MAJOR MITE ALLERGEN WITH CYSTEINEPROTEASE ACTIVITY

Recent reports have indicated that the cysteine protease activity of D er p 1 may play a significant role in its ability to elicit IgE antibo dy responses, mainly through cleavage of membrane CD23 on B cells and interleukin (IL)-4 synthesis and secretion from mast cells and basophi ls. Here we demonstrate for the first time that Der p 1 also cleaves t he alpha subunit of the IL-2 receptor (IL-2R or CD25) from the surface of human peripheral blood T cells and, as a result, these cells show markedly diminished proliferation and interferon gamma secretion in re sponse to potent stimulation by anti-CD3 antibody. Given that the IL-2 R is pivotal for the propagation of Th1 cells, its cleavage by Der p 1 may consequently bias thr immune response towards Th2 cells, thereby creating an allergic microenvironment.