Abstract: Described herein, are methods of detecting neutralizing antibodies that bind to Clostridioides difficile (C. diff) toxin B (TcdB), prognosing the disease severity of Clostridioides difficile infection (CDI) and the risk of primary and recurrent CDI, as well as providing a guide for clinical practice. Also described herein are kits for performing the methods of this disclosure.

Abstract: Novel, antibody-based binding agents derived from camelid VHH and human immunoglobulins are described. These binding agents recognize and bind with specificity to Clostridium difficile toxin A and/or toxin B and in some cases exhibit toxin neutralizing activity. These binding agents can be used to treat or prevent primary and recurrent CDI. The binding agents include humanized VHH peptide monomers, linked groups of humanized VHH peptide monomers, humanized VHH peptide monomers joined to antibody Fc domains, and humanized VHH peptide monomers joined to IgG antibodies.