Stability of anti-VLY scFvs during long-term storage. (A) Analysis of anti-VLY scFvs stored at the concentration of 0.65 mg/ml for 12 months by SDS-PAGE under reducing conditions. Lane 1 - 9B4-derived scFv (variant VH-VL); lane 2 - 23A2-derived scFv (variant VH-VL). Lane M - pre-stained protein molecular weight marker (Thermo Scientific Fermentas). (B) Testing of anti-VLY scFvs stored at the concentration of 0.65 mg/ml for 1, 6 and 12 months for the ability to neutralize VLY-mediated lysis of human erythrocytes.