DIRECTED SELECTION OF MIP-1-ALPHA NEUTRALIZING CCR5 ANTIBODIES FROM APHAGE DISPLAY HUMAN-ANTIBODY LIBRARY

The seven trans-membrane chemokine receptor CCR-5 is a coreceptor for macrophage tropic HIV-1 strains. CCR-5 responds to a number of chemoki nes, including macrophage inflammatory protein (MIP)-1 alpha. We descr ibe the use of MIP-1 alpha in a biotin tyramine-mediated proximity sel ection to guide the selection of CCR-5-specific phage antibodies from a large phage display human library. Proximity based selections result ed in a population of antibodies recognizing CCR-5 on primary CD4(+) l ymphocytes, none of which blocked MIP-1 alpha binding to cells. The se lected population of phage antibodies were subsequently used as guide molecules for a second phase of selection that was carried out in the absence of MIP-1 alpha. This generated a panel of CCR-5-binding antibo dies, of which around 20% inhibited MIP-1 alpha binding to CD4(+). The single chain Fvs (scFv) generated by this step-back selection procedu re also inhibited MIP-1 alpha-mediated calcium signaling.