A plain mesoporous silica nanoparticle without any immunomodulatory molecules significantly enhances anticancer immunity in vivo. Comprehensive mechanism of mesoporous-silica-nanoparticle-induced cancer immunotherapy is analyzed in this paper. The mesoporous silica nanoparticle promotes both Th1 and Th2 immune responses, as it accelerates lymphocytes proliferation, stimulates IFN-γ, IL-2, IL-4, and IL-10 cytokine secretion by lymphocytes ex vivo, and increases IgG, IgG1, IgG2a, IgM, and IgA antibody titers in mice serum compared with those of alum and adjuvant-free groups. Moreover, the mesoporous silica nanoparticle enhances effector memory CD4(+) and CD8(+) T cell populations in three most important immune organs (bone marrow, lymph node, and spleen) of mice compared with those of alum and adjuvant-free groups three months after adjuvant injection. The present study paves the way for the application of mesoporous silica nanoparticle as immunoadjuvant for cancer immunotherapy.

Hollow and non-hollow mesoporous silica nanospheres are synthesized and used for cancer vaccine adjuvants. The hollow structure of mesoporous silica nanospheres significantly promote cellular uptake of a model cancer antigen by macrophage-like cells in vitro, improve anti-cancer immunity, CD4(+) and CD8(+) T cell populations in splenocytes of mice in vivo.

A plain mesoporous silica (MS) nanoparticle without any immunomodulatory molecules enhances anti-cancer immunity in vivo. On page 1169, X.P. Wang, N. M. Tsuji, A. Ito and co-workers show that a plain MS nanoparticle promotes both Th1 and Th2 immune responses, and enhances the effector memory of CD4(+) and CD8(+) T cell populations in the three most important immune organs (bone marrow, lymph node and spleen) of mice.

Hollow and non‐hollow mesoporous silica nanospheres are synthesized and used for cancer vaccine adjuvants by X. Wang, A. Ito, N. M. Tsuji, and co‐workers on page 3510. The hollow structure of mesoporous silica nanospheres significantly promotes cellular uptake of a model cancer antigen by macrophage‐like cells in vitro, improves anti‐cancer immunity, and increases CD4+ and CD8+ T cell populations in splenocytes of mice in vivo.

In the original version of this article, there was an error in Figure S1a. The correct figure is shown below:This correction does not affect the overall conclusions of the results, and the authors apologize for any confusion caused. Figure S1. MS promoted effector memory T cell population (CD44 high CD62L -) in CD4 + (a).