Fab4meD is an academic technology platform harnessing the power of phage display to discover fragment antibodies (FABs) that bind selected targets with high affinity and specificity. FABs combine light and heavy chain portions that contain the antigen (Ag)-binding domain of an antibody (Ab). The resulting FAB is smaller than a normal Ab and expressible as a recombinant protein, while preserving a high affinity for the Ag. The coupling of a large library of FABs, either immune or naïve, to phages via recombinant DNA technology permits high affinity screening of Ab directed to various targets at relatively low cost. Following the isolation of FABs directed against a cell, a protein or other molecules or organelles, the FAB is cloned in an appropriate expression vector and the specificity and affinity of the expressed recombinant FAB for target binding is determined. In the case a target is a whole cell, a subtractive step using control cells is usually included prior to screening per se and the FAB ligand is then identified using immunoprecipitation coupled with mass spectrometry (IP-MS).