The insect cell-baculovirus expression vector system, widely usedfor glycoprotein production, is not ideal for pharmaceutical glycoprotein production due to the characteristics of the
N-glycansin the expressed products. Insect cells lack several enzymesrequired for mammalian-type
N-glycan synthesis and contain aspecific
N-acetylglucosaminidase that stunts the growth of chainsand a core
-1,3-fucosyltransferase that yields potentially allergenicglycoforms. Current knowledge on
N-glycan processing in lepidopteran insect cells is summarized, and strategies to developbetter glycoprotein expression systems suitable for pharmaceuticalglycoprotein production are discussed.