Cell lines having genetically modified
glycosylation pathways that allow them to carry out a sequence of enzymatic reactions, which mimic the
processing of glycoproteins in humans, have been developed. Recombinant proteins expressed in these engineered hosts yield glycoproteins more similar, if not substantially identical, to their human counterparts. Thelower eukaryotes, which ordinarily produce high-
mannose containing N-glycans, including unicellular and multicellular fungi are modified to produce N-glycans such as Man5GlcNAc2 or other structures along human
glycosylation pathways. This is achieved using a combination of
engineering and / or selection of strains which: do not express certain enzymes which create the undesirable complex structures characteristic of the fungal glycoproteins, which express
exogenous enzymes selected either to have optimal activity under the conditions present in the fungi where activity is desired, or which are targeted to an
organelle where optimal activity is achieved, and combinations thereof wherein the
genetically engineered eukaryote expresses multiple
exogenous enzymes required to produce “human-like” glycoproteins.