Immunological studies of Aging. III. Cytokinetic basis for the impaired response of lymphocytes from aged humans to plant lectins.

Abstract

The basis for the age-associated defect in the response of lymphocytes to plant lectins was studied. Using 3 independent assays, the number of mitogen-responsive cells is markedly reduced in lymphocyte preparations from old persons. Studies using colchicine block and thymidine pulse techniques revealed a failure of mitogen-response cells from old persons to expand into a proliferating pool of lymphocytes as is observed when lymphocytes from young persons are cultured with phytohemagglutinin. The impaired response of lymphocytes from old persons to mitogens is attributable to a reduced number of mitogen responsive cells and their failure to undergo clonal expansion.