Rapid way to obtain high expression clones of mammalian cells using a methylcellulose and immunoprecipitation screening method

1. The method for selecting eukaryotic clones highly expressing a polypeptide of interest from a population of eukaryotic cells expressing said polypeptide of interest comprising:

(a) culturing said population of eukaryotic cells on a semi-solid culture medium;

(b) contacting said population of cultured eukaryotic cells with a capture molecule that interacts with said polypeptide of interest, wherein the concentration of said capture molecule is between about 0.2 and 2.0 mg/ml, and said capture molecule comprises a detectable label;

(c) incubating said population of cultured eukaryotic cells expressing said polypeptide of interest with said capture molecule for a period of time;

(d) measuring the relative size of haloes produced by said detectable label following interaction of said polypeptide of interest with said capture molecule and wherein high expressing eukaryotic clones have a halo with a width that is equal to, or greater than, the radius of a eukaryotic cell clone lacking a halo; and

(e) selecting at least one of said high expressing eukaryotic cell clones from said population of said eukaryotic cells.

2. The method according to claim 1 , wherein said capture molecule is an antibody or a polypeptide binding fragment thereof.

3. The method according to claim 1 , wherein said detectable label is selected from the group consisting of: a chemical label, a biological label, a fluorescent label and a radioactive label.

4. The method according to claim 1 , wherein the semi-solid culture medium comprises a gelatinization agent comprising cellulose or agar.

5. The method according to claim 1 , wherein said eukaryotic cells are selected from the group consisting of: mammalian cells, yeast cells and insect cells.

6. The method according to claim 5 , wherein said mammalian cells are selected from the group consisting of: COS-1, COS-7, HEK293, HK21, CHO, BSC-1, HepG2, 653, SP2/0, 293, NSO, DG44 CHO, CHO K1, HeLa, myeloma, and lymphoma cells, or any derivative, immortalized or transformed cells thereof.

7. The method according to claim 1 , wherein said polypeptide of interest is a soluble polypeptide.

8. The method according to claim 1 , wherein said polypeptide of interest is an immunoglobulin or at least a portion thereof.

9. The method according to claim 1 , wherein the capture molecule is selected from the group consisting of a portion of a ligand wherein the portion binds to the polypeptide of interest, a portion of a receptor wherein the portion of said receptor binds to the polypeptide of interest, and an antibody that binds to the polypeptide of interest.

10. The method according to claim 9 , wherein said capture molecule is an antibody that binds said polypeptide of interest.

11. The method according to claim 1 , wherein the cells are myeloma cells, said polypeptide of interest is an immunoglobulin, the capture molecule is an antibody against the immunoglobulin, and the semi-solid culture medium is methylcellulose based.

12. The method according to claim 1 , wherein the concentration of said capture molecule is 1.0 mg/ml.

13. The method according to claim 1 , wherein said polypeptide of interest is at least one member selected from the group consisting of: a growth factor, a cytokine, a blood protein, a neurotransmitter, and a pharmacologically active peptide, or any portion or derivative thereof.

14. The method according to claim 1 , wherein said polypeptide of interest is an antagonist of at least one member selected from the group consisting of: growth factors, cytokines, blood proteins, neurotransmitters, and pharmacologically active peptides, or portions or derivatives thereof.

15. The method according to claim 14 , wherein said antagonist is at least one member selected from the group consisting of: an antibody, an antibody fusion, and an antibody fragment, or any portion or derivative thereof.