Oligonucleotide-directed mutagenesis of antibody combining sites.

We review here our attempts to achieve a better understanding of the structure--function relationship of antibody combining sites, and to gain insights into the engineering of antibodies with desired specificity and affinity. We have focused on a model system--antibodies to the hapten p-azophenylarsonate (Ars) derived from A/J mice. Oligonucleotide-directed mutagenesis was used to alter the sequence of the variable region genes of such anti-Ars antibodies. Mutant antibodies were generated in hybridoma cells following transfection of the altered genes, and the effects of the primary structure changes on antibody specificity, affinity, and idiotypic expression were assessed. These studies suggest that an antibody combining site with basic specificity for an antigen could be created by introducing a set of a few amino acid residues in the complementarity determining regions, and that the affinity of such a site could be improved one substitution at a time in a sequential manner.