Cytoskeleton Is Critical for the Formation of the Immunological

The binding of a T cell to an APC results in T cell actin cy-toskeletal rearrangement leading to the formation of an im-munological synapse. The APC cytoskeleton has been thought to play a passive role in this process. In this study, we demon-strate that dendritic cells (DC), unlike other APC, actively po-larize their actin cytoskeleton during interaction with T cells. DC cytoskeletal rearrangement was critical for both the clus-tering and the activation of resting T cells. This study provides compelling evidence that the APC cytoskeleton plays an active role in the immunological synapse and may explain the unique ability of DC to activate resting T cells. The Journal of Im-munology, 2001, 166: 1452–1456. S ustained TCR engagement, which is important for produc-tive T cell activation, depends on the formation of an im-munological synapse (1–3). This specialized contact be-tween the T cell and the APC is dependent on reorganization of the T cell actin cytoskeleton and is characterized by the accumulatio