Figure 4: Binding of human PLG to L. interrogans proteins by affinity blotting. Total protein extracts were resolved by 10% SDS-PAGE and electroblotted into nitrocellulose membranes. The membranes were incubated with PLG (a) or PLG + ACA (b), and the binding was detected by anti-PLG antibodies and peroxidase-conjugated antibodies. The reactivity was revealed by ECL (GE Healthcare) and exposure to X-Ray films. NV: high passage, nonvirulent L. interrogans serovar Copenhageni strain M 20; Vir: low-passage, virulent L. interrogans serovar Copenhageni strain Fiocruz L1-130. The arrows indicate reactivity protein regions seen in the virulent but absent in the nonvirulent bacterial extract. Positions of protein molecular mass markers are shown on the left.