Study Of The Expression And The Function Of CD137 On Endothelial Cells

Endothelial cells(ECs)play a wide variety of critical roles in the control of vascular function. Indeed, the accumulating knowledge of the endothelial cell structure as well as of the functional properties of the endothelial cells shifted their role from a passive membrane or barrier to a complex tissue with complex functions adaptable to needs specific in time and location.Endothelial cells can also be activated by various stimuli, such as thrombin or histamine, marked by a switch in their synthetic profile from basal conditions towards an activated state that is pro-thrombotic, pro-proliferative and vasoconstricting.ECs expressed MHC classâ…¡molecules and provide antigen-dependent signals to T cells in vitro and in vivo. However, this primary signal is not usually sufficient for full activation of the T cell. A second, costimulatory signal is also required and consists of interactions between cell surface ligands on the EC and specific receptors on the T cell. Human ECs do not express B7.1 or B7.2, but instead provide costimulatory signals through the binding of CD40-CD40L, CD58(LFA-3)-CD2(LFA-2), OX40-OX40L, PD-1-PD-1L/PD-2L and ICOS-ICOSL to induce T cell activation, and significantly up-regulates expression of cytokines such as IL-2. The activating and inhibiting costimulatory signals are delivered to the T cell from antigen-presenting cells (APCs), mediating and modulating T-cell clonal expansion and development of effector functions, as well as costimulatory signals that are delivered by activated T cells to interacting target cells.As there are many co-stimulatory receptors, a reasonable hypothesis is that several co-stimulatory signals are required for the development of effective T-cell immunity in any given situation.Acknowledging that some redundancy exists, the requirement for many or...