COSELECTION OF COGNATE ANTIBODY-ANTIGEN PAIRS BY SELECTIVELY-INFECTIVE PHAGES

We have developed a chloramphenicol resistant derivative of fd phage w ith which cognate pairs of antibodies and antigens can be selected, Th e phage genome encodes a fusion of single-chain antibody to the C-term inal domain of gIIIp, rendering the phage non-infective, The antigen f used to the N-terminal domains of gIIIp is encoded in the same phage g enome, Antigen and antibody fusion interact with each other in the per iplasm of the phage-producing cell, restoring infectivity, This system has a very low background and will allow simultaneous randomisation o f antibody and antigen.