Chinese hamster ovary cell mutants with multiple glycosylation defects for production of glycoproteins with minimal carbohydrate heterogeneity.

The production of glycoproteins with carbohydrates of defined structure and minimal heterogeneity is important for functional studies of mammalian carbohydrates. To facilitate such studies, several Chinese hamster ovary mutants that carry between two and four glycosylation mutations were developed. All of the lines grew readily in culture despite the drastic simplification of their surface carbohydrates. Therefore, both endogenous glycoproteins and those introduced by transfection can be obtained with specifically tailored carbohydrates. The lectin resistance properties of the mutants showed that each line expresses a novel array of cell surface carbohydrates useful for identifying specific roles for carbohydrates in cellular interactions. In addition, they showed that the epistatic relationships among different glycosylation mutations are not entirely predictable, providing insight into the complexity of the carbohydrate structures at the Chinese hamster ovary cell surface.