LIGHT-CHAIN SHUFFLING OF A HIGH-AFFINITY ANTIBODY RESULTS IN A DRIFT IN EPITOPE RECOGNITION

Human polyclonal and monoclonal antibodies against pathogens and toxin s are potentially useful in the treatment of various diseases. A numbe r of human monoclonal antibodies with protective capacity in vitro hav e been established by conventional hybridoma technology. However, with the development of phage-display technology, the possibility of speci fically tailoring antigenbinding properties has improved substantially . We show here that the reactivity of a high affinity, virus-neutraliz ing human antibody against the AD-2 epitope of cylomegalovirus gB can be modified by introducing other V kappa sequences together with the o riginal VH sequence. The fine specificity, as determined by the requir ement of particular amino acid residues in the epitope, is shifted in these new antibody fragments. It was also evident that the VH/V kappa pairing was not promiscuous, since antibody fragments selected by phag e display retained light chain sequences very similar to the original hybridoma-derived light chain, proving that a high affinity interactio n was very dependent on a co-operativity between both variable domains . These findings show that phage display technology might modify the b inding properties of pre-existing, high affinity antibodies.