The present data further demonstrate that a subpopulation of B cells which were functionally deleted during aging can be revived in vivo with 7m8oGuo. This compound is a member of a family of derivatized ribonucleosides which are potent B-cell activators and adjuvants. Using this compound as a probe to revive aged hyporesponsive B cells of CBA/CaJ mice, it was demonstrated that a subpopulation of B cells functionally deleted by the aging process can be readily tolerized by DHGG in that they fail to respond to AHGG in the presence of 7m8oGuo. It appears that this compound directly affects the B cells, since it has previously been shown that another derivatized nucleoside with identical lymphocyte-modulating properties has no effect on Th cells once they have been tolerized to DHGG. B cells stimulated by the combined effect of AHGG and 7m8oGuo were more readily tolerized in aged than in young adult mice.