Isolation of Monoclonal Neutralizing Single-Domain Antibodies Against Clostridioides difficile Toxin B

Area of Science:

• Microbiology
• Immunology
• Pharmacology

Background:

• Clostridioides difficile infection (CDI) is a prevalent nosocomial infection.
• Toxins A and B are key virulence factors contributing to CDI pathogenesis.
• Neutralizing these toxins presents a viable therapeutic strategy for CDI.

Purpose of the Study:

• To isolate and characterize single-domain antibodies targeting Clostridioides difficile toxin B.
• To enhance the neutralizing efficacy of these antibodies through homodimerization.
• To evaluate the therapeutic potential of these engineered antibodies in preclinical models.

Main Methods:

• Isolation of single-domain antibodies against the Clostridioides difficile toxin B CROPs domain.
• Engineering of homodimeric forms of potent neutralizing antibodies (TB5A7 and TB4A8).
• In vitro neutralization assays and in vivo protection studies against toxin B challenge.

Main Results:

• Identification of two effective single-domain antibodies, TB5A7 and TB4A8.
• Homodimeric forms of TB5A7 and TB4A8 demonstrated significantly enhanced neutralizing activity.
• The antibody dimers provided protection in animals challenged with a lethal dose of toxin B.

Conclusions:

• Engineered homodimeric antibodies targeting Clostridioides difficile toxin B exhibit superior neutralizing potency.
• These enhanced antibodies represent a promising therapeutic candidate for the development of novel agents against CDI.
• Further development of these antibody-based therapies could lead to effective treatments for C. difficile infections.