CLYBL and infection: Infection with Clb-Cnf+, Clb-Cnf- +pBK-cnf and Clb+Cnf+ resulted in more flattened cells, elongated cells or cells spreading out compared with infection with Clb-Cnf- (Figure 2a), which are hallmarks of CNF1 cytopathic effects in epithelial cells.34,41 Only HT-29 cells infected with Clb+Cnf+ and Clb+Cnf- +pBK-cnf exhibited both megalocytosis and elongated cell morphologies.