ALTERED SWITCH IN LIPID-COMPOSITION DURING T-CELL BLAST-TRANSFORMATION IN THE HEALTHY ELDERLY

Decreased mitogen responsiveness of lymphocytes during aging correlate s inversely with membrane microviscosity;; which reflects an altered l ipid composition. Therefore, we addressed the question, whether age-re lated alterations of lipid metabolism affect the switch in lipid compo sition during formation of blasts. Membrane lipids and fatty acids of peripheral blood lymphocytes from SENIEUR protocol compatible (''healt hy'') elderly donors (66-77 yr) and young controls (18-30 yr) were qua ntified after incubation with or :without the mitogen phytohaemaggluti nin. The blastic change in membrane lipid composition was different fo r young controls with respect to cholesterol, phosphatidylethanolamine , total phospholipids, as well as several fatty acids. Moreover, the a ge-related alterations in the switch of membrane lipids and fatty acid s were significantly correlated with a decreased mitogen response. Thu s, the alterations in membrane reorganization during blast formation o f lymphocytes from the elderly point to a disturbed cellular lipid hom eostasis with possible impact an the age-related reduction in immune f unction.