Relationship between lymphocyte response to tetanus toxoid and age of lymphocyte donor.

An investigation of the in vitro responsiveness of peripheral blood lymphocytes to tetanus toxoid was undertaken to determine the extent to which such reactivity might reflect in vivo reactions to tetanus toxoid immunization. It was found that lymphocyte transformation in the presence of tetanus toxoid, as measured by the uptake of tritiated thymidine, did not differ significantly for the group giving local or systemic reactions to tetanus toxoid and an immune control group. However, a striking inverse relation between lymphocyte reactivity to tetanus toxoid and age of the cell donors of both groups became clear. Such an age-related decline in the in vitro responsiveness of peripheral blood lymphocytes to a specific antigen has apparently had not been reported previously in man.