Methods of preventing and removing trisulfide bonds

A method for reducing the formation of trisulfide bonds in antibodies or antigen-binding fragments thereof, wherein said method comprises cultivating mammalian cells producing said antibodies or antigen-binding fragments thereof in cell culture media under conditions selected from the group consisting of:

• (a) maintaining or reducing the concentration of sulfur or sulfur-containing compounds in the cell culture media below a threshold level of 10 millimolar;
• (b) harvesting the cell culture media when the cell culture is at approximately maximum cell density or at approximately peak production of the antibodies or antigen-binding fragments thereof;
• and
• (c) a combination of (a) and (b), wherein the sulfur-containing compound is selected from:
• (i) hydrogen sulfide;
• (ii) sodium sulfide;
• and
• (iii) sodium hydrogen sulfide.