Age related impairment in phosphatidylinositol breakdown of polymorphonuclear granulocytes.

It is well known that with aging the immune response decreases. Most of the effector functions occur through specific receptors. Thus, we investigated the effects of various stimulants, acting through receptors or directly through the GTP-binding Gi protein, on phosphatidylinositol breakdown in PMNLs of young and elderly subjects and try to modulate it. A marked decrease in inositol phosphate (IP1, IP2, IP3) formation in PMNLs of elderly was found under FMLP stimulation when compared to that of young subjects. Neither GTP gamma S, nor AIF4- could induce an increase of IP3 in PMNLs of elderly comparable to that of young subjects. The results suggest that at least an alteration exists at the GTP-binding Gi protein level, as well as in the mechanism of linkage of the receptor to the G protein.