USE OF LIVING COLUMNS TO SELECT SPECIFIC PHAGE ANTIBODIES

Here we demonstrate that it is possible to confront two recombinant mi croorganisms in order to select one using the other. We have shown tha t an epitope derived from p21ras expressed within the outer membrane p rotein, LamB, can be recognized both by the monoclonal antibody Y13-25 9, as well as the single chain Fv fragment derived from it. This speci ficity, which is maintained when the Y13-259 single chain Fv is expres sed as a fusion protein with the phage fd gene 3 protein, has allowed us to use the living column of LamB-ras to purify Y13-259 phage from a background of non-binding phage, even at dilutions as high as 10 phag e in 10(10) irrelevant phage.