In this approach an antibody, specific for the molecule of interest (bait) or any tag expressed within a fusion protein, is used to separate the bait from a molecular mixture or a cell lysate and to capture its ligand simultaneously. The partners that bind to the bait molecule retained by the resin can then be eluted and identified. The antibody may be free or bound to a matrix during this process. [ http://www.ncbi.nlm.nih.gov/pubmed/7708014 ]