Engineering O -glycosylation in modified N -linked oligosaccharide (Man 12 GlcNAc 2 ∼Man 16 GlcNAc 2 ) Pichia pastoris strains

Yeast have been engineered for the production of therapeutic glycoproteins with humanized -linked oligosaccharides. Both - and -linked oligosaccharides engineered yeast have been attractive prospects, since yeast-specific -mannosylated proteins were reported to induce an aberrant immune response and alter pharmacokinetics . In the present study, we genetically manipulated -glycosylation by disrupting -mannosyltransferase and in a low-mannose type -linked oligosaccharide (Man GlcNAc ∼Man GlcNAc ) engineered strain to produce therapeutic glycoproteins. The -mannosyltransferase mutant produces anti-Her-2 antibodies with reduced -linked oligosaccharides and protein degradation, but this strain exhibited growth defects. However, the deletion of -mannosyltransferase individually has a minimal effect on -glycosylation, degradation of the anti-Her-2 antibody, and strain growth. Thus, by disrupting -mannosyltransferase in an -glycosylation engineered strain, we generated an effective glycoengineered strain to effectively produce therapeutic glycoproteins with both engineered - and -linked oligosaccharides.