IMMUNOLOGICAL FUNCTIONS OF AGED HUMAN MONOCYTES

Aging is associated with an increased occurrence of infection and canc er, and, as people age, they begin to exhibit age-related immune defic iencies, collectively termed immunosenescence. To determine the effect s of age on human monocytes, 'aged monocytes' (isolated from individua ls greater than or equal to 65 years of age) were compared with 'young monocytes' (isolated from individuals similar to 25 years of age) for their ability to be activated by lipopolysaccharide. Our results show that aged monocytes display a decrease in their cytotoxicity against tumor cells in vitro, a decrease in interleukin (IL1) secretion (altho ugh no decrease in IL1 precursor production was observed), a decrease in reactive oxygen and nitrogen intermediate (ROI/RNI) release, an inc rease in intracellular levels of cyclic adenosine monophosphate and a loss of protein kinase translocation. Therefore, aged monocytes presen t distinct characteristics of immunosenescence.