Fig. (4) Evaluation of immune response and purification of anti−sfGFP−mutacin IgG.(A) Reactivity of blood sera from sfGFP−mutacin immunized rabbit was ELISA tested against, sfGFP (0.5 μg/well) and mutacin (2 μg/well) or in the absence of antigens (No Ag). Serum samples (diluted to 1:5000) were taken from the immunized rabbit at several time points (days) from the first injection onwards. Antibody/ antigen interaction was detected by goat anti−rabbit HRP conjugated antibody (1:4000). (B) Protein−A affinity purification of IgG from rabbit serum. Five ml of diluted rabbit serum (at day 60) were injected (inject) onto HiTrap Protein−A column and washed with phosphate buffer (void) to remove the unbound proteins (flow−through), before eluting pure IgG (eluate).