7B and C), expression of both TCR forms was rescued. Surprisingly, under these conditions cska-TCRs accumulated at much higher levels (up to 200% of their expression in the nonactivated state) than the non-cska-TCRs (up to 75% of their expression levels in nonactivated cells), in the same cells (Supporting Information Fig.

7B and C). Levels of the T-cell-specific ZAP-70 PTK, which served as control, were unchanged (Supporting Information Fig. 7B). These results suggest that following activation most TCRs become associated with the cytoskeleton. Despite the massive downregulation of cell surface-expressed TCRs upon activation, low levels of surface receptors are maintained for the completion of T-cell activation [11]. However, the identity of these stably expressed surface TCRs remained unknown. We demonstrate that selleckchem while levels of cell surface expressed non-cska-TCRs were dramatically reduced following activation, levels of cell surface expressed cska-TCRs were only slightly reduced (Fig. 3A, left panel). Thus, the majority of TCRs expressed on the surface of activated T cells (after 14 h) belong to the cska population, despite the total recovery of both TCR populations to normal levels within the cell (Fig. 3A, right panel). We next followed the effect of cska-TCRs on the outcome of long-term activation

and assessed their effect on the capacity of the WT and MUT cells to secrete cytokines (IL-2) upon TCR-mediated

activation. The results revealed that the MUT cells secreted check details significantly less Liothyronine Sodium IL-2 than the WT cells (Fig. 3B). Upon activation with PMA and ionophore, which bypass the TCR, no differences between the MUT and WT cells in IL-2 secretion were observed, indicating a similar capacity of both cells to produce/secret IL-2 when activated via pathways that circumvent the TCR (Fig. 3B). Assessment of the capacity of the WT and MUT cells to synthesize cytokines revealed that the MUT cells synthesized significantly lower amounts of IL-2 compared with the WT cells (Fig. 3C). In addition, differences between MUT and WT cells were also observed in the induction of the cell surface expressed activation-dependent markers, CD25 and CD69 (Fig. 3D and F). Moreover, we also demonstrate that successfully activated WT T cells can affect the corresponding APCs, leading to the induction of CD25 and CD69 on their cell surface (Fig. 3E and G). In contrast, activated MUT T cells did not support CD25 and CD69 induction on the APCs (Fig. 3E and G), most likely due to the lack of IS formation and aberrant MUT cells activation. Dynamic regulation of TCR expression levels, TCR membrane reorganization, and interaction with intracellular molecules are key processes in modulating T-cell responses.