Myeloma cell culture in transferrin-free low iron medium

Abstract

The present invention relates to a method for culturing mammalian cells in a culture medium which is transferrin free and which contains no lipophilic or synthetic nitrogen-containing chelators. Also provided is the use of the medium and a process for providing a mammalian product by culturing cells capable of producing the product in the medium.

We claim: 
     
         1 . A method for the in vitro culture of a myeloma cell line which comprises:
 (a) inoculating a culture medium with a myeloma cell line, said medium being capable of supporting the growth of said myeloma cell line and comprising iron at concentrations in the medium of from about 0.03 mg/L to about 3.2 mg/L,   wherein said medium does not contain transferrin, a lipophilic chelator, a synthetic nitrogen-containing chelator or a lipophilic synthetic nitrogen-containing chelator; and   (b) growth of the inoculated culture medium under appropriate conditions and using agitated suspension culture.   
     
     
         2 . The method of  claim 1  wherein the concentration of iron in the medium is from about 0.03 mg/L to about 2.4 mg/L. 
     
     
         3 . The method of  claim 1  wherein the concentration of iron in the medium is from about 0.064 mg/L to about 1.6 mg/L. 
     
     
         4 . The method of  claim 1  wherein the concentration of iron in the medium is from about 0.16 mg/L to about 0.32 mg/L. 
     
     
         5 . The method of  claim 1  wherein the source of iron is a soluble iron compound. 
     
     
         6 . The method of  claim 5  wherein the soluble iron compound is selected from the group consisting of ferrous or ferric salts or simple chelates thereof. 
     
     
         7 . The method of  claim 6  wherein the soluble iron compound is selected from the group consisting of ferrous sulphate, ferrous citrate, ferric citrate and ferric ammonium compounds. 
     
     
         8 . The method of  claim 7  wherein the ferric ammonium compound is selected from the group consisting of ferric ammonium citrate, ferric ammonium oxalate, ferric ammonium fumarate, ferric ammonium malate and ferric ammonium succinate. 
     
     
         9 . The method of  claim 7  wherein the ferric ammonium compound is ferric ammonium citrate. 
     
     
         10 . A method for the in vitro culture of a myeloma cell line which comprises:
 (a) inoculating a culture medium with a myeloma cell line, said medium being capable of supporting the growth of said myeloma cell line and comprising ferric ammonium citrate at a concentration in the medium of from about 0.2 mg/L to about 20 mg/L, wherein said medium does not contain transferrin, a lipophilic chelator, a synthetic nitrogen-containing chelator or a lipophilic synthetic nitrogen-containing chelator; and   (b) growth of the inoculated culture medium under appropriate conditions and using agitated suspension culture.   
     
     
         11 . The method of  claim 10  wherein the ferric ammonium citrate is present in the medium at a concentration of from about 0.2 mg/L to about 15 mg/L. 
     
     
         12 . The method of  claim 10  wherein the ferric ammonium citrate is present in the medium at a concentration of from about 0.4 mg/L to about 10 mg/L. 
     
     
         13 . The method of  claim 10  wherein the ferric ammonium citrate is present in the medium at a concentration of from about 1 mg/L to about 2 mg/L. 
     
     
         14 . The method of  claim 1  wherein the medium is serum free, protein free, free of components of animal derivation or is chemically defined. 
     
     
         15 . The method of  claim 1  wherein the myeloma cell line is selected from the group consisting of an NSO series, a P3 series, MOPC series, MPC-11, J558L, K6H6/B5, 45.6.TG1.7, Y0, Y3 HTK, RPMI 8226 and U266B1. 
     
     
         16 . The method of  claim 1  wherein the myeloma cell line is an NSO cell line. 
     
     
         17 . A process for obtaining a mammalian cell product comprising culturing a myeloma cell capable of producing said product under agitated suspension culture and in a culture medium capable of supporting the growth of said myeloma cell line, said medium comprising iron at concentrations in the medium of from about 0.03 mg/L to about 3.2 mg/L, or ferric ammonium citrate at a concentration in the medium of from about 0.2 mg/L to about 20 mg/L, wherein said medium does not contain transferrin, a lipophilic chelator, a synthetic nitrogen-containing chelator or a lipophilic synthetic nitrogen-containing chelator; and recovering said mammalian cell product. 
     
     
         18 . The process of  claim 17  wherein the concentration of iron in the medium is from about 0.03 mg/L to about 2.4 mg/L. 
     
     
         19 . The process of  claim 17  wherein the concentration of iron in the medium is from about 0.064 mg/L to about 1.6 mg/L. 
     
     
         20 . The process of  claim 17  wherein the concentration of iron in the medium is from about 0.16 mg/L to about 0.32 mg/L. 
     
     
         21 . The process of  claim 17  wherein the source of iron is a soluble iron compound. 
     
     
         22 . The process of  claim 21  wherein the soluble iron compound is selected from the group consisting of ferrous or ferric salts or simple chelate thereof. 
     
     
         23 . The process of  claim 21  wherein the soluble iron compound is selected from the group consisting of ferrous sulphate, ferrous citrate, ferric citrate and ferric ammonium compounds. 
     
     
         24 . The process of  claim 23  wherein the ferric ammonium compound is selected from the group consisting of ferric ammonium citrate, ferric ammonium oxalate, ferric ammonium fumarate, ferric ammonium malate and ferric ammonium succinate. 
     
     
         25 . The process of  claim 24  wherein the ferric ammonium compound is ferric ammonium citrate. 
     
     
         26 . The process of  claim 17  wherein the ferric ammonium citrate is present in the medium at a concentration of from about 0.2 mg/L to about 15 mg/L. 
     
     
         27 . The process of  claim 17  wherein the ferric ammonium citrate is present in the medium at a concentration of from about 0.4 mg/L to about 10 mg/L. 
     
     
         28 . The process of  claim 17  wherein the ferric ammonium citrate is present in the medium at a concentration of from about 1 mg/L to about 2 mg/L. 
     
     
         29 . The process of  claim 17  wherein the medium is serum free, protein free, free of components of animal derivation or is chemically defined. 
     
     
         30 . The process of  claim 17  wherein the myeloma cell line is selected from the group consisting of an NSO series, a P3 series, MOPC series, MPC-11, J558L, K6H6/B5, 45.6.TG1.7, Y0, Y3 HTK, RPMI 8226 and U266B1. 
     
     
         31 . The process of  claim 17  wherein the myeloma cell line is an NSO cell line. 
     
     
         32 . The process of  claim 17  wherein the cell product is selected from the group consisting of polypeptides, proteins, hormones, lymphokines, interleukins and industrially and therapeutically useful enzymes. 
     
     
         33 . The process of  claim 32  wherein the cell product is an antibody or fragment thereof.