ABSTRACT
Three significant developments in molecular biology have been central in promoting the growing role of antibodies as tools for biochemical and biological research and as a significant class of molecules for drug development. First, following the establishment of reliable methods for the generation of high-affinity, high-specificity monoclonal antibodies from the natural immune response of mice and other species (1), recombinant DNA techniques have made it possible to isolate the corresponding complementary DNA (cDNA) encoding these antibodies, determine their sequences, and with the
help of structural information, optimize their antigen-binding properties through manipulation of their genes. Second, combinatorial approaches to protein engineering such as phage display (2) have made it possible to explore many more variants of antibodies than would typically be accessible in a site-directed mutagenesis approach (discussed in earlier chapters). Third, the elucidation of high-resolution molecular structures of antibodies have revealed some of the general features required for structural stability and antigen recognition (3,4). These approaches provide not only a means for the rapid optimization of antigen-binding properties of existing antibodies as discussed in this chapter, but also a means for the discovery of novel antibody specificities from immunized, nonimmunized (naı¨ve), or synthetic sources of diversity, as discussed in later chapters. Humanization of nonhuman antibodies and affinity maturation of antibodies from hybridoma or diversity-library sources are two areas of antibody optimization that can often be most efficiently addressed using antibody-phage display.
