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YEAST‐BASED IMMUNOTHERAPY AGAINST CLOSTRIDIUM DIFFICILE INFECTION
Author(s) -
Zhu Yixuan,
Feng Hanping
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.777.16
Subject(s) - microbiology and biotechnology , clostridium difficile , toxoid , epitope , antibiotics , peptide , clostridium difficile toxin a , biology , pseudomembranous colitis , virology , immune system , antibody , immunology , immunization , biochemistry
The bacterium Clostridium difficile is the most common cause of nosocomial antibiotic‐associated diarrhea as well as the etiologic agent of pseudomembranous colitis, with the emergence of hypervirulent and antibiotic‐resistant strains, the incidence of mortality in C. difficile ‐associated disease (CDI) patients is increasing rapidly. CDI is mainly caused by the two C. difficile exotoxins TcdA and TcdB (as TcdA‐TcdB‐strains are avirulent). Current standard treatment for CDI using antibiotics causes the disruption of microflora and results in a relapse rate approaching 35%. While other interventions have been tried (e.g., probiotics, toxin‐absorbing polymers, and toxoid vaccines), neither prevention nor treatment strategies have kept up with the increased incidence and severity of this infection. Newer immune‐based therapies have been shown to be somewhat effective in clinical trials. We engineered strain of probiotic Saccharomyces yeast that produces a tetra‐specific, tetrameric binding agent derived from camelid immunoglobulins, which comprises linked first, second, third and fourth V H H peptide monomers. The binding agent ABAB, wherein the first and third monomers have binding specificity for epitopes of TcdA and the monomers are V H H peptide monomers AH3 and AA6, respectively, and wherein the second and forth monomers have binding specificity for epitopes of TcdB and the monomers are V H H peptide monomers 5D and E3, respectively. The ABAB binding agent was expressed from two different plasmid‐based expression systems within the yeast, resulting in either the secretion of binding agent into the culture supernatant (pCEV‐URA3‐AT‐ABAB) or display of binding agent on the yeast cell surface (pYZ008). The neutralizing effect of ABAB produced by the yeast was confirmed in vitro and stability of the yeast carrying the plasmid was verified for 80 generations in non‐selective media. To treat a disease symptom induced by C. difficile in mice, 10^9 cfu of an engineered strain of Saccharomyces yeast expressing the binding agent ABAB was administered to mice by intragastric gavage. Based on the survival rate, weight loss and diarrhea incidents throughout the course of infection, it was shown that ABAB delivered by Saccharomyces yeast protected mice from primary CDI.Mouse treated with PBS, URA3−/− (control) and pCEV‐ABAB URA3−/− yeast strains was monitored for weight loss and survival during CDI.Mouse treated with PBS, URA3−/− (control) and pCEV‐ABAB URA3−/− yeast strains was monitored for weight loss and survival during CDI.