Self-assembled ferritin nanoparticles using SpyCatcher/SpyTag multimerization of Mycobacterium tuberculosis TB10.4 protein induce potent immunogenicity.

Although Bacillus Calmette-Guérin (BCG) continues to play a role in alleviating tuberculosis as a global public health crisis, its potential to cause disseminated disease in immunocompromised individuals further limits its widespread use. However, traditional subunit vaccines face the challenge of weak immunogenicity. In this study, we employed the SpyCatcher/SpyTag system and a ferritin (Fer) nanoparticle (NP) to construct an NP-based vaccine targeting the non-region of difference antigen TB10.4. The construct comprises two components: a SpyCatcher003-Fer vector and SpyTag003-TB10.4 antigen, expressed in prokaryotic and eukaryotic systems, respectively. These components were self-assembled into the tuberculosis nanovaccine candidate, SpyCatcher-Fer-TB10.4 (SFT), in vitro. Compared with the monomeric TB10.4, subcutaneous immunization with SFT-without an adjuvant-markedly enhanced cell proliferation, promoted T lymphocyte activation, and stimulated multiple TB-related cytokines, with responses comparable to or exceeding those induced by BCG. These findings suggest that SFT is superior to conventional recombinant proteins and holds promise for eliciting immunoprotective effects similar to those of BCG in the future.