A β-glucan-conjugate vaccine and anti-β-glucan antibodies are effective against murine vaginal candidiasis as assessed by a novel in vivo imaging technique

The protective capacity of a parenterally administered β-glucan-conjugate vaccine formulated with the human-compatible MF59 adjuvant was assessed in a murine model of vaginal candidiasis. To monitor infection, an in vivo imaging technique exploiting genetically engineered, luminescent Candida albicans was adopted, and compared with measurements of colony forming units. The vaccine conferred significant protection, and this was associated with production of serum and vaginal anti-β-glucan IgG antibodies. Vaginal IgG molecules were the likely mediators of protection as inferred by the efficacy of passive transfer of immune vaginal fluid and passive protection by an anti-β-1,3-glucan mAb. Overall, the in vivo imaging technique was more reliable than vaginal CFU counts in assessing the extent and duration of the vaginal infection, and the consequent protection level.