Phosphoinositide fatty acid composition of peripheral blood lymphocytes from aging humans.

ABSTRACT

The interaction of the T-cell receptor complex with the ligands is associated with early molecular events involved in the process of signal transduction implicating phosphoinositide breakdown. In elderly people, abnormalities in membrane signal transduction pathways are the basis of the immune deficiency associated with aging. Peripheral blood lymphocytes from aging humans and young subjects were stimulated with anti-CD3 monoclonal antibody and the phosphoinositide fractions were analyzed in order to determine the fatty acid composition in resting and stimulated conditions. In aging humans, in resting conditions, the all three phosphoinositide fractions appeared more saturated than the corresponding fractions in young subjects. Following anti-CD3 stimulation a decrease in arachidonic acid relative molar content was detected in both young and old subjects, but the arachidonic acid content in resting conditions greatly differed between the two groups, suggesting a different modulation of the microenvironment of the T-cell receptor complex in elderly people, so determining alterations in the early activation steps of lymphocytes.