Clones resistant to the lectins phytohemagglutinin (PHA), wheat germ agglutinin (WGA), the agglutinin(s) from Lens culinaris (LCA), and ricin (RIC) have been selected from parental auxotrophic Chinese hamster ovary (CHO) cells. The sensitivity to other lectins of these cells and of CHO cells resistant to concanavalin A (ConA) has been determined, and their activity of UDP-N-acetyl-glucosamine glycoprotein N-acetyl-glucosaminyltransferase (GlcNAc-T) has been measured. At least 8 different phenotypes have been identified on the basis of this analysis, and complementation between 2 of them demonstrated.