We examined the structural components of pertussis toxin that are required for efficient export from Bordetella pertussis via the Ptl system, a member of the type IV family of macromolecular transporters. First, we constructed a strain of B. pertussis that contains a functional Ptl system but does not produce pertussis toxin. Plasmids which express either the S1 subunit or the B oligomer were t...

Shiga toxin (Stx)-producing E. coli (STEC) cause food-borne outbreaks of hemorrhagic colitis. The main virulence factor expressed by STEC, Stx, is an AB5 toxin that has two antigenically distinct forms, Stx1a and Stx2a. Although Stx1a and Stx2a bind to the same receptor, globotriaosylceramide (Gb3), Stx2a is more potent than Stx1a in mice, whereas Stx1a is more cytotoxic than Stx2a in cell cult...

Pertussis toxin is one of the major virulence determinants produced by Bordetella pertussis. The DNA encoding the structural genes for pertussis toxin was cloned in Escherichia coli, and pertussis toxin subunit S4 was expressed under the control of the tac promoter. Mutations were introduced into the cloned toxin genes, and a conjugative shuttle vector system was devised for delivering the muta...

background and aims: among the bacterial agents, the most common cause of diarrheal disease is entrotoxigenic escherichia coli. letal toxin b (ltb) subunit of lt toxin could induce six-month immunity. clostridium botulinum causes botulism disease. bont/a-hc toxin subunit could induce two years immunity against this disease. it seems that the immunogenicity potency of these two subunits may infl...

Chapter 1: Introduction and Literature Review Chapter 2: Low dose exposure and immunogenicity of transgenic maize expressing the Escherichia coli heat-labile toxin B subunit Chapter 3: Immunogenicity of daily and intermittent oral administration of transgenic maize expressing the Escherichia coli heat-labile toxin B subunit Chapter 4: Discussion Acknowledgements iii

ipad gene is amongst key genes in shigella invasion, known as an antigen. pa20 protein of bacillus anthracic can be separated from native pa protein during the infection and can be found in the serum of the infected patients and make it possible to diagnose the disease. ctxb, a known immune adjuvant, enhances the immunogenicity and is mainly used for the production of recombinant vaccines as a ...

BACKGROUND Vibrio cholerae O1 El Tor dominated the seventh cholera pandemic which occurred in the 1960s. For two decades, variants of V. cholerae O1 El Tor that produce classical cholera toxin have emerged and spread globally, replacing the prototypic El Tor biotype. This study aims to characterize V. cholerae O1 isolates from outbreaks in Thailand with special reference to genotypic variations...

The B subunit of Shiga toxin and the Shiga-like toxins (SLTs) mediates receptor binding, cytotoxic specificity, and extracellular localization of the holotoxin. While the functional receptor for Shiga toxin, SLT type I (SLT-I), and SLT-II is the glycolipid designated Gb3, SLT-II variant (SLT-IIv) may use a different glycolipid receptor. To identify the domains responsible for receptor binding, ...

Chapter 1: Literature Review I. Allergic Responses II. Animal Allergy Models III. Cholera Toxin and Heat Labile Toxin Chapter 2: Cholera Toxin or Escherichia coli Heat Labile Toxin Subunit B and Mouse Peanut Allergy Model I. Abstract I