Isolating Cells Expressing Secreted Proteins

A method of high expression of a protein of interest, comprising:

• (a) transfecting a mammalian cell with (i) a nucleic acid encoding the protein of interest and (ii) a nucleic acid encoding a cell surface capture molecule that comprises a membrane anchor and is capable of binding the protein of interest;
• (b) culturing the mammalian cell under conditions in which the protein of interest and cell surface capture molecule are expressed, and a protein of interest-cell surface capture molecule complex is formed and displayed on the cell surface of the mammalian cell;
• (c) contacting the mammalian cell with a detection molecule that binds to the protein of interest-cell surface capture molecule complex;
• and
• (d) detecting and isolating the mammalian cell that displays on the cell surface the binding of the detection molecule with the protein of interest-cell surface capture molecule complex.

A method of isolating a mammalian cell with high expression of a secreted protein of interest (POI), comprising:

• (a) transfecting a mammalian cell with a nucleic acid that encodes a secreted POI and a cell surface capture molecule capable of binding the POI, wherein the secreted POI and the cell surface capture molecule are both expressed by the cell, wherein the cell surface capture molecule comprises a protein, or a functional fragment thereof which comprises a membrane anchor;
• (b) culturing the cell under conditions in which the POI and cell surface capture molecule are expressed, and a POI-cell surface capture molecule complex is formed and displayed on the cell surface;
• (c) contacting the cell with a detection molecule, which binds to the POI displayed by the cell;
• and
• (d) detecting and/or isolating the cell due to it being bound to the detection molecule.