Glycosylation profiles of the human colorectal cancer A33 antigen naturally expressed in the human colorectal cancer cell line SW1222 and expressed as recombinant protein in different insect cell lines.
The A33 antigen is a cell surface glycoprotein expressed in human gastrointestinal epithelium and in 95% of colorectal cancers. We have compared the N-linked glycosylation profile of A33 antigen naturally expressed in a human colorectal cancer cell line with recombinant human A33 antigen (rA33) produced in insect cell culture using the baculovirus expression vector. N-Linked glycans were enzymatically released from the protein, and glycan composition was analyzed by HPLC. In three insect cell lines tested (Sf-21, Tn5B1-4, and Tn-4s), glycosylation of rA33 was dominated by high mannose structures (M5Gn2 to M9Gn2; 78-95% of total N-linked glycans), with M8Gn2 being the single most abundant glycoform. A33 antigen naturally expressed in the SW1222 human colon cancer cell line (A33) also possessed a high abundance of high mannose glycans (72%). No complex glycosylation was detected on rA33 expressed in insect cells. Natural A33 was galactosylated to a small extent (6%). These results illustrate a case of similar glycosylation of a glycoprotein between a recombinant version produced in insect cell culture and its counterpart naturally expressed in human cell culture.
Joosten
Christoph E
CE
Cornell University-Ludwig Institute for Cancer Research Partnership Laboratory, Stocking Hall, Ithaca, New York 14853, USA.
Cohen
Leonard S
LS
Ritter
Gerd
G
Batt
Carl A
CA
Shuler
Michael L
ML
D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D015179:Colorectal Neoplasms / Q000276:immunology* / Q000473:pathology; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D006801:Humans; D007313:Insecta / Q000166:cytology; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism*; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism
C104258:GPA33 protein, human; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins