T Cell Control of Extracellular Matrix Degradation

Matrix metalloproteinases (MMP) are members of an enzyme family the extent of whose involvement in physiological and pathological situations is just beginning to be appreciated. A case in point is the vast array of normal and exacerbated immunological responses involving T cell recruitment to a particular site in the organism through the extracellular matrix (ECM). In order to penetrate and migrate through the ECM, T cells need to lyse their way through a variety of connective tissue proteins. We review herein the available evidence for a role of MMPs secreted by T cells to allow them to migrate. We will then examine the data indicating that MMPs are not solely secreted by migrating T cells but that adjacent stromal cells also do their part, Finally, we will review a number of instances where MMP dysregulation is associated with some important T-cell dependent pathologies.