Recombinant protein rMBP-NAP restricts tumor progression by triggering antitumor immunity in mouse metastatic lung...

Recombinant Helicobacter pylori neutrophil-activating protein fused with maltose-binding protein (rMBP-NAP), a potential TLR2 ligand, was reported to possess immunomodulatory effects on in situ tumors in our previous study. In the present work, we attempt to elucidate the effect of rMBP-NAP at the local immune modulation in B16-F10-induced metastatic lung cancer. Our results demonstrated that growth of B16-F10 melanoma metastases in the lung was significantly arrested after rMBP-NAP treatment, along with marked reduction in metastatic lung nodules and significant increase in survival. The treatment induced both local and systemic immune responses, which were associated with higher influx of CD4⁺/CD8⁺ T cells and drove toward Th1-like and cytotoxic immune environment. Moreover, rMBP-NAP also showed significant anti-angiogenic activity by reducing vascularization in lung tumor sections. rMBP-NAP could induce antitumor immunity through activating Th1 cells and producing pro-inflammatory cytokines, which are responsible for the effective cytotoxic immune response against cancer progression. Our findings indicate that rMBP-NAP might be a novel antitumor therapeutic strategy.