Effect of advanced aging on ability of mice to cause regression of an immunogenic lymphoma in response to immunotherapy based on depletion of suppressor T cells.

This study shows that two therapeutic agents, anti-CD4 mAb and vinblastine, capable of causing T-cell-mediated regression of an established L5178Y lymphoma in 3-month-old mice, are incapable of causing regression of this tumor in 20- to 22-month-old mice. It is known that both agents are immunoaugmentative because of their ability to destroy tumor-induced CD4+ suppressor T cells preferentially. Therefore, the results indicate, that aged mice, unlike young mice, are not capable of generating therapeutic numbers of CD8+ effector T cells in the absence of suppressor cells.