The corn smut-made cholera oral vaccine is thermostable and induces long-lasting immunity in mouse

•Stability and immunogenicity of a corn smut CTB-based cholera vaccine are reported.•The vaccine induced toxin neutralizing IgA responses in mice at 15 μg doses.•The vaccine is highly thermo stable and induced long lasting immunity.

The use of corn smut for the production of recombinant vaccines has been recently implemented by our group. In this study, the stability and immunogenic properties of the corn smut-based cholera vaccine, based on the cholera toxin B subunit (CTB), were determined in mouse. The immunogenic potential of distinct corn smut CTB doses ranging from 1 to 30 μg were assessed, with maximum humoral responses at both the systemic (IgG) and intestinal (IgA) levels at a dose of 15 μg. The humoral response last for up to 70 days after the third boost. Mice were fully protected against a challenge with cholera toxin after receiving three 15 μg-doses. Remarkably, the corn smut-made vaccine retained its immunogenic activity after storage at room temperature for a period of 1 year and no reduction on CTB was observed following exposure at 50 °C for 2 h. These data support the use of the corn smut-made CTB vaccine as a highly stable and effective immunogen and justify its evaluation in target animal models, such as piglet and sheep, as well as clinical evaluations in humans.