Relationship betweenlymphocyte response totetanus toxoid andageoflymphocyte donor

SUMMARY Aninvestigation oftheinvitro responsiveness ofperipheral blood lymphocytes totetanus toxoid wasundertaken todetermine theextent towhichsuchreactivity mightreflect invivo reactions totetanus toxoid immunization. Itwasfound that lymphocyte transformation inthepresence oftetanus toxoid, asmeasured bythe uptake oftritiated thymidine, didnotdiffer significantly forthegroupgiving local orsystemic reactions totetanus toxoid andanimmunecontrol group. However, a striking inverse relation between lymphocyte reactivity totetanus toxoid andageofthecell donors ofbothgroups becameclear. Suchanage-related decline intheinvitro responsiveness ofperipheral bloodlymphocytes toaspecific antigen hasapparently notbeenreported previously inman.