Many mammalian proteins with potential pharmaceutical applications are glycosylated by their native host cells. Since the carbohydrate on many glycoproteins has been shown to be important for intermolecular recognition and stability in vitro and in vivo, it may be necessary to produce glycosylated forms of the proteins as pharmaceutical products. Production of such proteins in microorganisms by means of recombinant DNA techniques offers advantages of economy and virtually unlimited supply, and we have demonstrated that the yeast Saccharomyces cerevisiae accurately glycosylates the proper asparagine residues of the human serum protein alpha-1-antitrypsin (AAT) as it is secreted into the culture broth.
The aim of this proposed work is to determine if the various patterns of carbohydrate added by different yeast strains carrying mutations in the glycosylation pathway (1) provide in vitro and in vivo stability to AAT beyond that observed for unglycosylated AAT, and (2) raise no new antibodies in an animal model beyond those raised by AAT isolated from human serum. If these results are obtained, then this yeast glycosylation and secretion system should allow economical and unlimited production of non-immunogenic glycosylated AAT and other mammalian glycoproteins.
