INTERLEUKIN-12 RELEASE BY MITOGEN-STIMULATED MONONUCLEAR-CELLS IN THEELDERLY

Defects involving cellular expression of activation molecules, cell me diated immune response and natural killer (NK) activity are commonly o bserved in the elderly. Herein, data are reported on the evaluation of IL-12 production by old subjects. IL-12 is, actually, considered the key molecule for the induction of a T helper 1 (Th1) -type and NK resp onse. IL-12 production from old subjects peripheral blood mononuclear cells (PBMNC) was evaluated using T-independent (bacterial lipopolysac charide, LPS) or -dependent (phytoemagglutinin, PHA; immobilized anti- CD3 monoclonal antibodies, anti-CD3) mitogens. The IL-12 production af ter LPS stimulation was not reduced in cultures from old subjects when compared to that from young ones. On the contrary, IL-12 production b y PHA or anti-CDS stimulated PBMNC from old subjects was decreased. Fu rthermore, we have demonstrated a reduced CD40 and CD40 ligand (CD40L) expression on PBMNC from old subjects. This finding fits very well wi th the reduced cytokine production observed in the T-dependent stimula tion systems, being the CD30-CD40L interaction mandatory for an effici ent IL-12 production. All together, these results seem to suggest that defects in cell `expression of activation molecules can affect the IL -12 secretion and in consequence other Th1-type cytokines. (C) 1998 El sevier Science Ireland Ltd. All rights reserved.