Generation of aglycosylated antibody-producing mice

Aberrant protein glycosylation IS frequently observed in vanous disease states including cancer, thereby making efforts to utilize a specific glycoprotein of a protein as a disease biomarker feasible. The immunoassay using biomarker-specific antibodies is one of the most reliable, robust and convenient methods. Conceptually, the combination of an antibody and a lectin (or glycan- specific antibody) may enable detection of a specific glycoform of a biomarker when applied to the sandwich ELISA platform. However, the glycans m immunoglobulin G interfere with the interactions between an antigen and a lectin, thereby making such immunoassay fundamentally unfeasible. Several efforts have been made to overcome this problem including deglycosylation using PNGase-F, enzymicdigestion of an antibody using pepsin, and chemical modifications of glycans of antibodies. However, such efforts rendered unsatisfactory analytical outcomes. To resolve this matter fundamentally, we genome-engineered mice by mutating the N-glycosylation consensus site (asparagine-coding codon) into non-asparagine coding sequences. We found that aglycosylated antibodies were produced in the genome-engineered mice following immunization with antigens. The stability of the aglycosylated antibodies produced from the engineered mice was equivalent to that of conventional antibodies. Moreover, the aglycosylated antibody in combination with a lectin was reliably applicable to the ELISA platform to quantify a specific glycoform with diagnostic validity. The genome-engineed mice can also be used as a host for generation of an aglycosylated antibody to measure a specific glycoform of biomarkers.