Figure 5. Calpain inhibition decreases proliferation of peripheral blood T cells in vitro.

a.- representative histograms of VPD450 fluorescence of gated CD4⁺ (black histograms, left panels) and CD8⁺ lymphocytes (grey histograms, right panels) obtained after 72 and 120 hours in culture where PBMC were stimulated with immobilized anti-CD3 and untreated or treated with 10 μM calpain inhibitor II (CI II) or with 10 μM calpain inhibitor IV (CI IV) as described in Materials and Methods. b.-e. significantly reduced dynamic proliferation parameters of CD4⁺ cells treated with calpain inhibitors as above. b. - reduction of proliferation index after 120 hours in culture (PI 120), c. - reduction of average number of divisions performed by a dividing precursor cell during 120 hours of culture, d. - increased average length of a cell cycle, e. - decreased average time from contact with stimulant to the onset of G1 phase of first division. Means ⁺/− SD are shown, N = 12. P values obtained using the paired Student T test are shown for significant differences.