P2X(7) receptors and apoptosis in tuberculosis infection

Immune cells express P2 purinoceptors of the P2Y and P2X subtypes. Evidence accumulated has shown that many different cell types are killed by sustain ed exposure to high concentrations of extracellular ATP. Depending on the A TP dose, length of stimulation and receptor subtype, P2X receptor stimulati on may cause necrosis or apoptosis. Triggering of apoptosis, in response to intracellular infection, has been identified for a wide range of pathogens and host organisms, and there is now emerging interest about mechanism med iating host cell death and its role in pulmonary tuberculosis. The physiolo gical meaning of P2X receptor-dependent cell death is not completely unders tood, but and involvement in immune-mediated reactions is postulated.