C2GnT-I is expressed in 1D4^– HH cells but has minimal enzyme activity. (A). RT-PCR (for C2GnT and β-actin) and (B) immunoblotting (for C2GnT) demonstrate abundant expression of C2GnT mRNA and protein in all cell lines. (C) Extracts of HUT78, MyLa2059, and HH cells were assayed for C2GnT enzyme activity. **P < .001, HUT78 compared with HH; *P < .01, Myla2059 compared with HH. Values are means ± SD of duplicates from 1 of 5 independent experiments.