Controlling Fucosylation Levels of Antibodies with Osmolality during Cell Culture

Because defucosylation levels (deFuc%) of monoclonal antibodies (MAbs) must be regulated for quality control, it is quite important to analyze the factors that affect deFuc%. For the MAbs produced in the rat hybridoma cell line YB2/0, we found that osmolality of the culture medium is the major determinant of deFuc%. deFuc% was linearly correlated with osmolality, with r2 being as high as 0.92. In addition, deFuc% was not affected by the type of compound used for controlling osmolality (NaCl, KCl, fucose, fructose, creatine and mannitol). We succeeded in controlling deFuc% of MAbs by maintaining medium osmolality constant during cultures (for both perfusion and fed-batch cultures).