The activity of μ-calpain is increased while that of m-calpain is reduced in the B-CLL cells compared with B cells of healthy people.

Lysates of peripheral blood lymphocytes and immunomagnetically enriched B cells (CD3⁻) of a healthy 67-year-old and of the same number of B-CLL cells from 2 age-matched patients (CLL 1, CLL 2) were prepared in PBS and tested by zymography. The lysate treated with calpain inhibitor II served as specificity control (CLL 2 inh). Std indicates the activities of standard μ- and m-calpain as in Figure 1. This is a representative zymogram of 1 of 5 experiments giving similar results. The inhibitory effects of calpain inhibitor II, calpeptin, and rabbit muscle calpastatin were similar.