Research Article

Eryptotic Phenotype in Chronic Myeloid Leukemia: Contribution of Neutrophilic Cathepsin G

Figure 3

In vitro studies to delineate the role of cathepsin G in the proteolysis of band 3. Heat-stressed normal (N) erythrocytes were incubated with IgG-depleted/complement-inactivated sera from the same individual and also with sera from CML patients designated C (N2 with C6, N3 with C10 and N5 with C13) at 37°C for 20 min. Western blots prepared from the lysates of these erythrocytes were stained with cathepsin G and band 3 antibodies. (a) Cathepsin G levels are higher in the membrane of erythrocytes incubated with CML sera as compared to normal sera. (b) Staining of the same blot with anti-band 3 antibody shows that a 20 kDa fragment of band 3 is seen in cells incubated with CML sera. (c) The generation of 20 kDa fragment is diminished upon incubation with pepstatin A (pep) and is nearly inhibited by cathepsin G inhibitor 1 (CI). Densitometric readings of each lane of the band 3 autograph corresponding to the lanes in (c) demonstrate equal loading.
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