Patent ID: 8227199

Claim:
A method for identifying an immunobinder that specifically binds to a cell surface antigen of interest comprising: (a) providing a plurality of immunobinder-expressing cells comprising a first sortable label; (b) providing a plurality of antigen-expressing cells comprising a second sortable label, wherein the antigen of interest is displayed at the surface of the antigen-expressing cell; (c) contacting the antigen-expressing cells with the immunobinder-expressing cells; and (d) separating from the plurality of immunobinder-expressing cells, one or more immunobinder-expressing cells that can specifically bind to the antigen expressing cells using a cell sorter, wherein the presence of the first and second sortable label in a single cellular complex is indicative of the binding of an immunobinder-expressing cell to an antigen-expressing cell, thereby identifying an immunobinder that binds to a antigen of interest.