Methods for increasing mannose content of recombinant proteins

A method for increasing the high mannose glycoform content of a recombinant protein during a mammalian cell culture process comprising:

• establishing a cell culture comprising mammalian cells in a bioreactor with a cell culture media that does not contain mannose;
• growing the mammalian cells during a growth phase with a cell culture media that does not contain mannose by a fed-batch process with supplemental bolus feeds of a feed medium containing mannose, wherein the mannose to total hexose ratio in the feed medium is greater than 0 but less than 1.0;
• initiating and maintaining a production phase in the cell culture by perfusion feeds, thereby producing the recombinant protein, and wherein the high mannose glycoform content of said recombinant protein is increased as compared to a cell culture where the mammalian cells are not subjected to a feed medium containing a mannose to total hexose ratio of greater than 0 and less than 1.0.