Enhanced immunogenicity of a Clostridioides difficile TcdB vaccine adjuvanted with a synthetic dual-TLR ligand adjuvant.

We report a comprehensive evaluation of the toxin B (TcdB) vaccine adjuvanted with a dual Toll-like receptor ligand liposome adjuvant for Clostridioides difficile infection (CDI). The vaccine completely protected mice from a lethal infection. Compared to alum adjuvanted TcdB, it generated functionally superior systemic antibodies and supported strong memory B cell and gut IgA responses. This pharmaceutically acceptable adjuvant platform holds promise for developing a next-generation CDI vaccine.