Standard Protocols for the Construction of Fab Libraries

Fab libraries, in which light-chain (LC) and heavy-chain (HC) variableregion genes are cloned into a phagemid vector and subsequently displayed on the surface of the filamentous phage particle, have been widely used for the isolation of antibodies (Abs) with specificity for haptens, foreign antigens (Ags), and self Ags. Immune Fab libraries, in which lymphoid tissue from individuals who, perhaps because of disease, have mounted an immune response to particular Ags, have been used in the recovery of Fabs with binding specificity for a number of clinically relevant Ags including c-erb B-2 (1 ) and p53 (2 ). Fab libraries are thus valuable as a means whereby the genes for Abs of interest can be immortalized and propagated. This enables information to be gathered regarding the Ab, including structural features, V-gene usage, and the nature of the immune response in the individual. Additionally, the isolated Abs can be used to evaluate immunogenic epitope(s) of the Ag. Furthermore, the Abs themselves provide potentially useful diagnostic or therapeutic agents (2 ). The isolation of Fabs from combinatorial libraries is thus valuable in contributing to the understanding of Ab-Ag interactions, as well as the nature of the in vivo immune response.