A novel nanomicelle composed from PEGylated TB di-peptide could be successfully used as a BCG booster

OBJECTIVE(S): Tuberculosis affects one-third of the world’s population and leads to a high rate of morbidity and mortality. Bacillus Chalmette–Guerin (BCG) as the only approved vaccine for the Mycobacterium tuberculosis (Mtb) does not show enough protection in the vaccinated population. MATERIALS AND METHODS: The main aim of this study was to prepare a self-assembled nanomicelle composed from a di-block polymer in which, a di-fusion peptide was the hydrophobic block and polyethylene glycol (PEG) was the hydrophilic block. The micelles were characterized in vitro and in vivo as an antigen delivery system/adjuvant both with and without a prime BCG. RESULTS: The micellar nanovaccine was able to elicit good dendritic cell maturation. Nanomicelles could efficiently induce systemic cytokines as well as nasal secretory predominant antibody titers (sIgA). The expression pattern of cytokines indicated the superiority of cellular immunity. Nasal administration of two doses of nanomicelles after a prime subcutaneous administration of BCG induced the highest mucosal and systemic immune responses. CONCLUSION: Based on our results PEG-HspX/EsxS self-assembled nanomicelle is highly immunogenic and can be considered a potential vaccine candidate against Mtb to boost BCG efficiency.