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Pathogenicity and Virulence
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Enterotoxins are those exotoxins that exert their activity in the gastrointestinal tract, producing symptoms such as nausea, vomiting, and diarrhea. Certain strains of E. coli, S. aureus, Salmonella, Shigella, Vibrio, and C. perfringens produce enterotoxins. Enterotoxin production may take place in contaminated food, as is the case with staphylococcal enterotoxin, or in the gastrointestinal tract as occurs with Salmonella and the other agents. Though the mechanisms of action vary, the end results are similar.
Battlefield Chemical Inhalation Injury
Published in Jacob Loke, Pathophysiology and Treatment of Inhalation Injuries, 2020
Staphylococcal cultures may produce a number of biologically active compounds that include one or more enterotoxins. Four distinct antigenic groups of enterotoxins are described (A, B, C, D). These enterotoxins are simple proteins, of which the type B toxin has been most extensively studied (Wagman et al., 1965; Lamanna and Carr, 1967).
Scientific Rationale for the Use of Single Herb Remedies in Ayurveda
Published in D. Suresh Kumar, Ayurveda in the New Millennium, 2020
S. Ajayan, R. Ajith Kumar, Nirmal Narayanan
Daswani et al. (2011) studied the anti-diarrheal activity of the decoction of C. rotundus tubers using representative assays of diarrheal pathogenesis. Antibacterial, antigiardial and antirotaviral activities were also studied. Effects on adherence of enteropathogenic Escherichia coli and invasion of enteroinvasive E. coli and Shigella flexneri to HEp-2 cells were evaluated to measure the effect on colonization. Effect on enterotoxins such as enterotoxigenic E. coli, heat-labile toxin, heat-stable toxin and cholera toxin was also assessed. The decoction showed antigiardial activity, reduced bacterial adherence to and invasion of HEp-2 cells and affected production of cholera toxin and action of heat-labile toxin. The decoction of C. rotundus seems to exert the anti-diarrheal action by mechanisms other than direct killing of the pathogen.
Immunomodulatory regulation by heat-labile enterotoxins and potential therapeutic applications
Published in Expert Review of Vaccines, 2021
Mary-Peyton A. Knapp, Taylor A. Johnson, Madison K. Ritter, Robert O. Rainer, Steven E. Fiester, Jennifer T. Grier, Terry D. Connell, Sergio Arce
Mutant enterotoxins may also decrease toxicity by reducing excessive inflammatory responses. According to Scharton-Kersten et al., HLTs lacking ADP-ribosyltransferase, as evidenced by mutant LT-I and CT compared to their respective holotoxins, seemed to attenuate the immune response to diphtheria toxin, while still conferring some immunogenicity [67]. A study tested the immunogenicity of LT-IIa, LT-IIb, LT-IIb (T13I), and LT-IIc when co-administered with RiVax antigen. The mutant LT-IIb (T13I) demonstrated the least amount of inflammatory response when administered with RiVAx compared to the other HLTs tested [62]. In another study, intranasal administration of LT-IIb (T13I) with RiVax antigen caused a significant increase in RiVax-specific antibody levels compared to RiVax alone. There was also an increase in IgG and IgA antibodies in BAL fluid, saliva and fecal samples. These findings demonstrated that LT-IIb (T13I) was not less effective than LT-IIb as an adjuvant even though it was less toxic [13]. Taken together, this data reveals that it is possible to use mutant forms of HLTs as adjuvants to stimulate immunogenicity while decreasing the toxicity of the wildtype forms through loss of cAMP activation and reduced inflammation.
B cells and upper airway disease: allergic rhinitis and chronic rhinosinusitis with nasal polyps evaluated
Published in Expert Review of Clinical Immunology, 2021
Harsha H Kariyawasam, Louisa K James
There is a high prevalence of nasal colonization with Staph. Aureus and associated enterotoxin production in CRSwNP [30]. Staph. Aureus enterotoxins (SAEs-SEA, SEB, SEC, SED, and toxic shock syndrome toxin) are classed as superantigens and present in high numbers in the epithelium and submucosa of CRSwNP tissue. Rapid polyclonal T-cell activation occurs as SAES are able to bind directly to the peptide-binding cleft and thus simultaneously cross-link multiple TCR molecules. SAEs can also lead to oligoclonal T-cell activation by binding to the variable region of the TCR β-chain (Vβ-domain). Such T-cell superantigens will also act as ‘super-allergens’ enabling B cells, in a nonspecific antigen manner, to produce IgE against SAE itself. SAEs, acting as superantigens, are for this reason likely to drive B-cell-driven production further of activating and immunoregulatory ‘super’ IgE and IgG antibodies which contribute to disease pathogenesis and sustenance [32].
Microbiota modulation-based therapy for luminal GI disorders: current applications of probiotics and fecal microbiota transplantation
Published in Expert Opinion on Biological Therapy, 2019
Abbinaya Elangovan, Jessica R. Allegretti, Monika Fischer
The pathophysiology of acute infectious diarrhea frequently involves one of the three mechanisms – ingestion of a preformed enterotoxin, production of an endotoxin following the ingestion of the culprit organism or inflammation of the intestinal epithelium by invasion of the organism [45].