Genetic and immunological analysis of a novel variant of Shiga toxin 1 from bovine Escherichia coli strains and development of bead-ELISA to detect the variant toxin.
A novel variant of Shiga toxin 1 (Stx1) was identified from bovine Escherichia coli strains. The stx1 variant genes designated as stx1v51 and stx1v52 were cloned and sequenced. The two variant genes differed each other by 2 bp, but the deduced amino acid sequences of the two Stx1 variant toxins were the same and had 94% and 92% homology to that of prototype A and B subunits of Stx1, respectively. The variant toxin designated as Stx1v52 was purified to homogeneity. Although inhibition of protein synthesis in vitro by purified Stx1v52 was almost equal to that of purified Stx1, Vero cell cytotoxicity and mouse lethality of Stx1v52 were several folds lower than those of prototype Stx1. In Ouchterlony double gel diffusion test, the precipitin line between Stx1v52 and Stx1 formed a spur against anti-Stx1 serum but was fused against anti-Stx1v52 serum. Stx1v52 and Stx1v52-specific-bead-ELISA was developed, and both Stx1 and Stx1v52 could be detected with high sensitivity using Stx1v52 conjugate. However, Stx1v52 but not Stx1 could be detected with Stx1v52-specific bead-ELISA.
Ohmura-Hoshino
Mari
M
Research Institute, International Medical Center of Japan, Shinjuku-ku, Tokyo 162-8655, Japan. mstar@ims.u-tokyo.ac.jp
Ho
Soon-Tae
ST
Kurazono
Hisao
H
Igarashi
Kazuei
K
Yamasaki
Shinji
S
Takeda
Yoshifumi
Y
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary; D014644:Genetic Variation; D005779:Immunodiffusion; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D011817:Rabbits; D017422:Sequence Analysis, DNA; D022622:Shiga Toxin 1 / Q000235:genetics* / Q000276:immunology* / Q000633:toxicity; D014709:Vero Cells
D022622:Shiga Toxin 1