In the quest to isolate monoclonal antibodies of therapeutic significance against selected targets using phage display approaches, success or failure largely depends on the nature of the target.Many targets are cell membrane bound,and whole cell-based biopanning strategies may be adopted to isolate antibodies.However there are a number of potential hindrances to the isolation of antibodies against membrane proteins, by whole cell biopanning.The problems include mammalian cell fragility, non-specific binding of phage to cell membranes, the integrity of the membranebound antigen during biopanning and the low abundance of many membrane-bound proteins of therapeutic significance.These potential problems may present significant challenges to the isolation of useful antibodies, and there are obvious advantages if the target antigen can be cloned and expressed in the native form.