Mammalian cell culture process

The process of claim 14 in which the host cell is a dp12.CHO cell line cell transfected with the vector carrying the cDNA for a soluble type 1 tumor necrosis factor immunoglobulin G1 TNFR1-IgG1 chimera.

A process for producing a tumor necrosis factor receptor-immunoglobulin TNFR1-IgG1 chimeric protein comprising;

• (a) culturing a mammalian host cell which expresses a TNFR1-IgG1 chimera in a growth phase under such conditions and for a period of time such that maximum cell growth is achieved;
• (b) culturing the host cell in a production phase in the presence of sodium butyrate at a concentration of bout 6 mM to about 12 mM;
• (c) maintaining the osmolality of the production phase at about 450-600 mOsm.

A process for producing a tumor necrosis factor receptor-immunoglobulin TNFR1-IgG, chimeric protein comprising;

• (a) culturing a mammalian host cell which expresses a TNFR-IG chimera in a growth phase under such conditions and for a period of time such that maximum cell growth is achieved;
• (b) culturing the host cell in a production phase in the presence of sodium butyrate at a concentration of about 1 mM to about 6 mM;
• (c) maintaining the osmolality of the production phase at about 300-450 mOsm.

A TNFR1-IgG1 preparation comprising TNFR1-IgG1 molecules wherein the TNFR1-IgG1 molecules have a molar ratio of sialic acid to protein of about 4-7.

A TNFR1-IgG1 preparation comprising TNFR1-IgG1 molecules wherein the TNFR1-IgG1 molecules have about 1-2 moles of exposed N-acetylglucosamine residues per mole-of TNFR1-IgG1 protein.

A TNFR1-IgG1 preparation comprising TNFR1-IgG1 molecules wherein the TNFR1-IgG1 molecules have a molar ratio of sialic acid to N-acetylglucosamine of about 0.35 to about O.5.