Disclosed are methods of identifying binding moieties that recognize antigens displayed on cells, such as membrane proteins or recombinant proteins that display eptiopes on the surface of cells. Binding moieties capable of binding membrane proteins can be difficult to obtain because these proteins can depend on their native environments for structural integrity. In some methods scFv phage display libraries are panned against whole cells expressing a membrane protein in an emulsion. Certain methods further permit discrimination of binding moieties according to their affinity or avidity for a target. This approach allows rapid identification of cell surface epitope specific antibodies for research, diagnostics, and immunotherapeutics.