Preparation of Mycobacterium tuberculosis EsxV lipid nanoparticles subunit vaccine and its immunological characteristics

Abstract:

To prepare a lipid nanoparticle (LNP)-based subunit vaccine of Mycobacterium tuberculosis (Mtb) antigen EsxV and study its immunological characteristics, the LNP containing EsxV and c-di-AMP (EsxV:C:L) was prepared by thin film dispersion method, and its encapsulation rate, LNP morphology, particle size, surface charge and polyphase dispersion index were measured. BALB/c mice were immunized with EsxV:C:L by nasal drops. The levels of serum and mucosal antibodies, transcription and secretion of cytokines in lung and spleen, and the proportion of T cell subsets were detected after immunization. EsxV:C:L LNPs were obtained with uniform size and they were spherical and negatively charged. Compared with EsxV:C immunization, EsxV:C:L mucosal inoculation induced increased sIgA level in respiratory tract mucosa. Levels of IL-2 secreted from spleen and ratios of memory T cells and tissue-resident T cells in mice were also elevated. In conclusion, EsxV:C:L could induce stronger mucosal immunity and memory T cell immune responses, which may provide better protection against Mtb infection.