Age-related impairment of the in vitro antibody response in the human

We have used trinitrophenyl polyacrylamide beads (TNP-PAA) to induce a primary in vitro antibody response toward TNP in cultures of peripheral blood lymphocytes (PBL) from aged individuals. The response was virtually non-existent whereas PBL from young control individuals were able to respond. Recombination experiments showed that: (1) aged PBL did not suppress the response of young PBL; (2) young T cells enhanced the response of aged (unfractionated or T-depleted) cells; (3) aged T cells were unable to restore the response of young T-depleted cells, in contrast to young allogeneic T cells. Upon stimulation with Concanavalin A (Con A) aged PBL displayed a moderately diminished proliferative response and a normal ability to suppress the anti-TNP response of autologous PBL (in the few responders). However, contrasting with young PBL they could not suppress the anti-TNP response of young allogeneic PBL.