Novel CagA ELISA exhibits enhanced sensitivity of Helicobacter pylori CagA antibody

Figure 1 Purification of recombinant East Asian-type CagA. A: CBB-stained 8% SDS-PAGE gel; 20 μg of protein were loaded per well. Lane 1: Uninduced lysate; 2: 0.4 mmol/L IPTG induced lysate; 3: Flow through; 4: Wash; 5: Elution. In the elution fraction (Lane 5), the 135 kDa band (arrowhead 1) is the full length rCagA. The 75-100 kDa rCagA cleavage product (arrowhead 2) comprised approximately 50% of the elution fraction; B: Western blot analysis with anti-CagA antibody. Lane 1: Uninduced lysate; 2: 0.4 mmol/L IPTG induced lysate; 3: Elution. Following induction (Lane 2), the full length GST-fused rCagA (*1) was expressed. However, it was subsequently cleaved (*2). In the elution fraction (Lane 3), the amount of full length rCagA was low (arrowhead 1) and various smaller-sized bands (arrowhead 2) were confirmed as rCagA fragments.