Significantly decreased amounts of both μ- (A,D) and m-calpain (B,E) in the CD4+(A,B) and CD8+(D,E) as well as of calpastatin (only in the CD8+; C,F) lymphocytes of old people regardless the expression or lack of CD28. Significantly higher amounts of both calpains in the CD4+CD28- vs. CD4+CD28+ of old people (A,B) but not in CD8+CD28- vs. CD8+CD28+ (D, E) lymphocytes of young as well as old subjects. Results are shown as bars for means (CD28+ (□) and CD28- (■) cells respectively) and whiskers for +/- SD. Statistical significance is indicated by asterisks at p<0.05(*) or p<0.001 (**). See Methods for the details.