costimulointi
Costimulation refers to a process in immunology where the activation of immune cells, particularly T cells, requires signals from at least two distinct receptors. The primary signal, often delivered through the T cell receptor (TCR) binding to an antigen presented by an antigen-presenting cell (APC), is insufficient on its own to elicit a full T cell response. A second, costimulatory signal is necessary to prevent anergy, which is a state of unresponsiveness, and to promote T cell proliferation, differentiation, and effector function.
Common costimulatory pathways involve interactions between surface molecules on T cells and APCs. A well-studied example
The absence of costimulatory signals during T cell activation can lead to tolerance or anergy, which is