Expression of scFv 32, 43 and 51 in E. coli. Panel A. Western blot analysis of lysates from cultures of the HB2151 E. coli strain expressing the scFv 32, 43 and 51, non induced (NI) or IPTG-induced for 2 and 4 hours at RT, before lysis. For the non induced cultures the total bacterial lysate was analysed, whereas pellet (P) and supernatant (S) fractions from the IPTG-induced cultures were utilized. Panel B. Western blot analysis of the total lysates from the M15/Rep+ E. coli strain expressing the scFv 32 and 51, non induced (NI) and IPTG-induced (I) for 4 hours at RT. The M15/Rep+ E. coli strain was used to repress the antibody expression in the non induced cultures. The Western blotting was performed using the anti-FLAG M2 mAb as a primary antibody, followed by GAM-HRP incubation. The immune complexes were revealed by chemiluminescence. Molecular mass markers are shown on the left.