Monocyte chemotactic responsiveness triggered by Lymphocyte-Derived Chemotactic Factor in aged donors. Definitive report.

Monocyte chemotactic responsiveness triggered by autologous Lymphocyte-Derived Chemotactic Factor (LDCF) has been evaluated in a group of aged donors. LDCF obtained from Peripheral Blood Lymphocytes (PBL) supplemented with varying numbers of monocytes from aged donors gave a lower chemotactic response when compared to young donors. Moreover, when cell suspensions were pretreated with indomethacin (INDO) before LDCF production, an enhancement of LDCF-induced chemotaxis was observed in old individuals, this implying a prostaglandin-mediated suppression on LDCF release in the elderly. This lymphokine seems to be produced by T cells and, above all, OKT8+ cells, whose frequency is lower in aging. Interestingly, LDCF obtained from OKT8+ enriched cells supplemented with autologous monocytes induced in aged donors a chemotactic activity comparable to that observed in young subjects. These data suggest that the lower frequency of OKT8+ cells in the aging may play a key role in the impairment of LDCF-mediated monocyte chemotaxis.