Normal and abnormal secretion by haemopoietic cells

The secretary lysosomes found in haemopoietic cells provide a very efficien t mechanism far delivering the effector proteins of many immune cells in re sponse to antigen recognition. Although secretion shows some similarities t o the secretion of specialized granules in other secretory cell types, some aspects of secretary lysosome release appear to be unique to melanocytes a nd cells of the haemopoietic lineage. Mast cells and platelets have provide d excellent models for studying secretion, but recent advances in character izing the immunological synapse allow a very fine dissection of the secreta ry process in T lymphocytes. These studies show that secretary lysosomes ar e secreted from the centre of the talin ring at the synapse. Proper secreti on requires a series of Rab and cytoskeletal elements which play critical r oles in the specialized secretion of lysosomes in haemopoietic cells.