Attenuated EHEC and clostridial toxins TcdA and TcdB based vaccine for Clostridium difficil associated disease (CDAD)
Inventors
Boedeker, Edgar C. • Kumar, Sudeep
Assignees
US Department of Veterans Affairs
Publication Number
US-10286054-B2
Publication Date
2019-05-14
Expiration Date
2033-10-11
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
Provided are novel methods for expressing antigens in a vaccine vector strain, a live oral vaccine designed to prevent clostridium difficile-associated disease and methods for delivering antigens to the mucosal immune system of a subject.
Core Innovation
The invention provides novel methods for expressing Clostridium difficile antigens in a vaccine vector strain, specifically using a live attenuated Enterohemorrhagic Escherichia coli (EHEC) vector strain, referred to as ZCR533. This live oral vaccine is designed to prevent Clostridium difficile-associated disease (CDAD) by inducing protective mucosal and systemic immunity to C. difficile toxins TcdA and TcdB. The ZCR533 strain has been genetically engineered to express the immunogenic C-terminal receptor binding portions of these toxins by incorporating their sequences into the passenger domain of the autotransporter protein EspP, thereby displaying toxin antigens on the bacterial surface or secreting them to elicit an immune response.
The problem addressed relates to the increasing incidence and severity of Clostridium difficile infection (CDI), particularly in hospitalized and elderly patients, with high morbidity, mortality, and substantial healthcare costs. Current treatments face challenges, including antibiotic resistance, frequent recurrences, and emerging more virulent C. difficile strains. The background emphasizes the urgent need for novel therapeutic and prophylactic approaches to CDI that can provide effective mucosal immunity, which the disclosed live oral vaccine aims to fulfill.
The vaccine utilizes the previously developed live attenuated EHEC vector strain ZCR533, which has deletions and mutations to abolish its native toxin activities while retaining important antigenic components. Into this vector, the C-terminal binding regions of TcdA and TcdB toxins are fused with EspP to be surface displayed or secreted, thereby presenting protective antigenic determinants to the mucosal immune system. Immunization with this vaccine is expected to induce anti-toxin immunity within the intestine and protect against C. difficile toxins, thus offering a new approach for both prevention and treatment of CDAD.
Claims Coverage
This patent discloses four inventive features derived from one independent claim centered on a vaccine composition and method to induce anti-TcdA and anti-TcdB antibodies using a live attenuated EHEC vector expressing specific toxin domains.
Live attenuated EHEC vector expressing TcdA and TcdB antigenic fragments
The method involves administering to a subject a live attenuated Enterohemorrhagic Escherichia coli (EHEC) comprising a cell binding domain of TcdA toxin or an antigenic fragment thereof, and a cell binding domain of TcdB toxin or an antigenic fragment thereof from Clostridium difficile. The TcdA corresponds to the 70 amino acids encoded by nucleotides 934-1144 of SEQ ID NO:3 and TcdB corresponds to the 70 amino acids encoded by nucleotides 723-933 of SEQ ID NO:3.
Use of specific nucleotide sequences encoding fusion antigens
The composition administered is encoded by the nucleotide sequence set forth in FIG. 13 (SEQ ID NO:3), which encodes the TcdA and TcdB fusion antigen incorporated into the autotransporter EspP.
Surface localization of TcdA and TcdB antigens
The TcdA and TcdB antigenic fragments expressed by the live attenuated EHEC vector are surface bound, presenting antigenic determinants directly on the bacterial surface.
Fusion of TcdA and TcdB antigenic domains in a single construct
The vaccine includes a fusion construct combining the 70 amino acid C-terminal cell binding domains of TcdA and TcdB toxins fused together in tandem within the passenger domain of the EspP autotransporter, enabling expression of both toxin antigens by the vector strain.
The claims focus on a live attenuated EHEC-based vaccine vector expressing specific C-terminal receptor binding domains of C. difficile toxins TcdA and TcdB as surface-displayed fusion antigens encoded by defined nucleotide sequences, thereby providing a method to induce anti-toxin antibodies in a subject.
Stated Advantages
Induces protective mucosal and systemic immunity against Clostridium difficile toxins via local intestinal immune responses.
Utilizes a live attenuated EHEC vector strain retaining key antigenic components for enhanced vaccine efficacy.
Surface display of toxin antigens via EspP autotransporter optimizes induction of mucosal immunity.
Provides a novel therapeutic and prophylactic approach addressing the rising incidence, virulence, and antibiotic resistance challenges of CDI.
Documented Applications
Prevention and treatment of Clostridium difficile-associated disease (CDAD) in hospitalized patients, elderly, and those receiving antibiotics.
Immunization of subjects at risk of CDI upon hospital admission to prevent primary infections.
Prevention of recurrent CDI in patients who have been treated for a primary episode and remain at risk due to ongoing intestinal microbiota disruption.
Interested in licensing this patent?