BACTERIAL EXPRESSION OF IMMUNOGLOBULIN FRAGMENTS

The expression of Ig fragments in Escherichia coli permits rapid acces s to engineered molecules with antigen-binding properties. While the e xpression in 'a functional state by secretion to the periplasm is the standard method for the production of Fv and Fab fragments, single cha in Fv fragments are mainly produced by refolding from insoluble aggreg ates. Although all of these Ig fragments serve as valuable aids in the study of antigen binding, their different biochemical properties must be considered when using them as research tools or for medical applic ations. In addition to these simple univalent antibody fragments, the bacterial expression of bivalent and bispecific versions and of hybrid proteins with novel effector functions is gaining increasing importan ce.