EFFICIENT CONSTRUCTION OF A LARGE NONIMMUNE PHAGE ANTIBODY LIBRARY - THE PRODUCTION OF HIGH-AFFINITY HUMAN SINGLE-CHAIN ANTIBODIES TO PROTEIN ANTIGENS

A large library of phage-displayed human single-chain Fv antibodies (s cFv), containing 6.7 x 10(9) members, was generated by improving the s teps of library construction. Fourteen different protein antigens were used to affinity select antibodies from this library. A panel of spec ific antibodies was isolated with each antigen, and each panel contain ed an average of 8.7 different scFv, Measurements of antibody-antigen interactions revealed several affinities below 1 nM, comparable to aff inities observed during the secondary murine immune response, In parti cular, four different scFv recognizing the ErbB2 protein had affinitie s ranging from 220 pM to 4 nM. Antibodies derived from the library pro ved to be useful reagents for immunoassays, For example, antibodies ge nerated to the Chlamydia trackomatis elementary bodies stained Chlamyd ia-infected cells, but not uninfected cells, These results demonstrate that phage antibody libraries are ideally suited for the rapid produc tion of panels of high-affinity mAbs to a wide variety of protein anti gens, Such libraries should prove especially useful for generating rea gents to study the function of gene products identified by genome proj ects.