Use of modified Clostridium perfringens enterotoxin fragments for claudin targeting in liver and skin cells by Beier, L, Rossa, J, Woodhouse, S, Bergmann, S, Kramer, H, Protze, J, Eichner, M, Piontek, A, Vidal-Y-Sy, S, Brandner, J, Krause, G, Zitzmann, N, Piontek, J