Autologous mixed lymphocyte reaction in man. X. T-T autologous mixed lymphocyte reaction in young and aging humans.

T cells upon activation with mitogens or autologous non T cells express surface HLA-DR antigens and are capable of stimulating autologous T cells in the autologous mixed lymphocyte reaction (T-T AMLR). We have examined T-TA AMLR, using T-non T AMLR activated-(TA) T cells as stimulators in young (21-32 yr) and aging humans (62-84 yr). In aging subjects a significantly (p less than 0 . 01) higher proliferative response was observed in T-TA AMLR as compared to simultaneously studied young subjects. In allogeneic MLR, no significant difference was observed between young and aging subjects. The increased T-TA AMLR could be a mechanism responsible for deficient T-non T AMLR reported in aging humans.