| pubmed-article:2278550 | pubmed:abstractText | It is well known that most physiological functions change with aging, including the immune response. Data concerning the aging of lymphocyte subpopulations are conflicting. The antigen density of peripheral blood lymphocytes has been determined by fluorescently tagged OKT-3, OKT-4, OKT-8, OKT-11 and OKM1 monoclonal antibodies in a carefully selected aged (over 87 years) population, and compared to that of young subjects. A substantial difference was found in the percentage distribution of OKT8 and OKM1 subsets. The volume of lymphocytes of the elderly population was significantly less than that of the young. The effect of various monoclonal antibodies on phosphatidylinositol breakdown has also been studied. It was found that only OKT3, acting through the CD3 antigen receptor, was able to induce inositol phosphate formation in both young and elderly, although in the latter population this occurred at a lower level. Because the plasma membrane plays a regulatory role in this process, an important and sensitive functional parameter, the membrane potential, was also monitored and influenced by changing the extracellular K+ concentration. The lymphocytes of the elderly population responded less sensitively to changes in extracellular potassium concentration. | lld:pubmed |
