Generation and characterization of a recombinant human CCR5-specific antibody - A phage display approach for rabbit antibody humanization

We describe the isolation of a CCR5-specific antibody, ST6, from an antibody phage display library generated from an immune rabbit. ST6 was previously shown to efficiently prevent; the surface expression of CCR5 when expressed intracellularly (Steinberger, P., Andris-Widhopf, J., Buhler, B., Torbett, B. E., and Barbas, C. F., III (2000) Proc. Natl. Acad. Sci. U. S. A. 97, 805-810). Because ST6 has therapeutic potential in human immunodeficiency virus, type 1 disease, its humanization was desired to minimize the potential for immunogenicity, ST6 was humanized using a phage display-based approach. Like the parental rabbit clone, the humanized version ST6/34 efficiently prevented the surface expression of CCR5. The conserved linear peptide epitope bound by these antibodies was mapped using phage display. Both ST6 as well as the humanized anti-CCR5 antibody ST6/34 were produced as complete IgG antibodies and shown to bind to cell surface CCR5.