The immune diversity in a test tube - Non-immunised antibody libraries andfunctional variability in defined protein scaffolds

Technologies to develop and evolve the function of proteins and, in particu lar, antibodies have developed rapidly since the introduction of phage disp lay. Importantly, it has become possible to identify molecules with binding properties that cannot be found by other means. A range of different appro aches to create general libraries that are useful for the selection of such molecules specific for essentially any kind of target have emerged. We her ein review some of the most prominent approaches in the field and in partic ular discuss specific features related to the development of antibody libra ries based on single antibody framework scaffolds. This approach not only p ermits identification of a range of specific binders, but also facilitates further evolution of initially derived molecules into molecules with optimi sed functions.