Shiga and Shiga-like toxins.

Although Shigella dysenteriae serotype 1 (Shiga) toxin was discovered more than 80 years ago (18) and has long been recognized as one of the most potent bacterial toxins (18, 116), early efforts to characterize its structure, biologic activity, genetics, role in pathogenesis, and other properties were hindered by difficulties in preparing pure toxin, obtaining appropriate immunologic reagents, and conducting genetic studies with S. dysenteriae 1. The enterotoxicity of Shiga toxin was first reported in 1972 (59). Other important advances that have been made during the past decade include the following: (i) purification of Shiga toxin to homogeneity (7, 21, 81, 87, 120); (ii) identification of cell surface receptors for toxin (8, 45; A. A. Lindberg, J. E. Brown, N. Stromberg, M. Westling-Ryd, J. E. Schultz, and K. A. Karlson, J. Bliol. Chem., in press; A. A. Lindberg, J. E. Schultz, M. Westling, J. E. Brown, S. W. Rothman, K. A. Karlsson, and N. Stromberg, Proc. FEMS Meet. Mol. Biol. Pathogenic Microorganisms, in press); (iii) demonstration that the intracellular action of toxin causes an inhibition of protein synthesis (7, 8a, 97, 111; T. G. Obrig, T. P. Moran, and J. E. Brown, J. Biol. Chem., in press); (iv) recognition