Cell culture medium and methods for enhancing recombinant antibody purity
This invention relates to a novel cell culture medium and methods to enhance recombinant antibody purity using the cell culture medium disclosed herein. The novel cell culture medium is a self-made feeding medium, which comprises from about 90 nM to about 500 mM cysteine, from about 50 mM to about 500 mM tyrosine, and from about 50 mM to about 300 tryptophan. This invention also relates to a method of growing cell culture using the cell culture medium disclosed herein By controlling the concentration of cysteine in the self-made feed medium as well as the amount and time of adding this feed medium into the cell culture, the purity of antibodies is significantly improved while glycosylation profile and antibody expression level are consistently maintained to guarantee the efficacy of antibodies.
1. A self-made feed medium comprising from about 90 mM to about 500 mM of cysteine, from about 50 mM to about 500 mM of tyrosine, and from about 50 mM to about 300 mM of tryptophan, wherein the pH of the self-made feed medium is equal or greater than about 10.
2. The self-made medium according to claim 1 , wherein the self-made medium comprises from about 100 mM to about 400 mM cysteine.
3. The self-made medium according to claim 1 , wherein the self-made medium comprises 120 mM to 300 mM cysteine.
4. The self-made medium according to claim 1 , wherein the self-made feed medium comprises from about 200 mM to about 400 mM of tyrosine, and from about 50 mM to about 150 mM of tryptophan.
5. The self-made medium according to claim 1 , wherein the pH of the self-made feed medium ranges from about 10 to about 12.
6. A method for culturing mammalian cells comprising the following steps:
1) seeding mammalian cells comprising nucleic acids encoding the antibody of interest in a basal culture medium to form a cell culture;
2) adding the self-made feed medium of claim 1 after the cell culture entering the exponential growth phase; and
3) monitoring cell viability and adjusting the culture duration time.
7. The method according to claim 6 characterized by further adding a fed-batch medium to the cell culture at the exponential growth phase.
8. The method according to claim 6 characterized by adding the self-made feed medium and the fed-batch medium to the cell culture every day or every 2-3 days beginning at culture day 3 for the entire culture duration time.
9. The method according to claim 8 , wherein the added total volume of the self-made feed medium and the fed-batch medium is from about 1% to about 50% of the present total cell culture volume, and wherein the volume ratio of the self-made feed medium to the fed-batch medium is about 1˜10:10˜100.
10. The method according to claim 8 , wherein the added total volume of the self-made feed medium and the fed-batch medium is from 1% to 20% of the present total cell culture volume, and wherein the volume ratio of the self-made feed medium to the fed-batch medium is about 1˜3:10˜20.
11. The method according to claim 8 , wherein the added total volume of the self-made feed medium and the fed-batch medium is from 1% to 10% of the present total cell culture volume, and wherein the volume ratio of the self-made feed medium to the fed-batch medium is about 1:10.
12. The method according to claim 8 characterized by adding the self-made feed medium and the fed-batch medium to the cell culture on culture day 3, 5, 7, 9 and 11.
13. The method according to claim 6 , wherein when the cell viability is lower than 90%, the culturing is terminated.