Recombinant Mycobacterium smegmatis delivering a fusion protein of human macrophage migration inhibitory factor (MIF) and IL-7 exerts an anticancer effect by inducing an immune response against MIF in a tumor-bearing mouse model.

In conclusion, our data showed that rSmeg-hMIF-hIL-7 exerts a strong antitumor immune response in mice, possibly by inhibiting the MIF-dependent promotion of tumorigenesis by the anti-MIF immune response and via enhanced cytotoxic T cell recruitment into tumor microenvironments. We also found that it also exerted an enhanced anticancer effect with immune checkpoint inhibitors. These results suggest that rSmeg-hMIF-hIL-7 is a potential adjuvant for cancer immunotherapy. This is the first report to prove anticancer potential of immunotherapeutic vaccine targeting immune response against MIF.