Microbiota-specific T follicular helper cells drive tertiary lymphoid structures and anti-tumor immunity against colorectal cancer.

The composition of the intestinal microbiota is associated with both the development of tumors and the efficacy of anti-tumor immunity. Here, we examined the impact of microbiota-specific T cells in anti-colorectal cancer (CRC) immunity. Introduction of Helicobacter hepaticus (Hhep) in a mouse model of CRC did not alter the microbial landscape but increased tumor infiltration by cytotoxic lymphocytes and inhibited tumor growth. Anti-tumor immunity was independent of CD8 ⁺ T cells but dependent upon CD4 ⁺ T cells, B cells, and natural killer (NK) cells. Hhep colonization induced Hhep-specific T follicular helper (Tfh) cells, increased the number of colon Tfh cells, and supported the maturation of Hhep+ tumor-adjacent tertiary lymphoid structures. Tfh cells were necessary for Hhep-mediated tumor control and immune infiltration, and adoptive transfer of Hhep-specific CD4 ⁺ T cells to Tfh cell-deficient Bcl6 ^fl/fl Cd4 ^Cre mice restored anti-tumor immunity. Thus, introduction of immunogenic intestinal bacteria can promote Tfh-associated anti-tumor immunity in the colon, suggesting therapeutic approaches for the treatment of CRC.
Competing Interests: Declaration of interests D.A.A.V., cofounder and stockholder – Novasenta and Tizona; stock holder – Oncorus and Werewolf; patents licensed and royalties – Astellas, BMS; scientific advisory board member – Tizona, Werewolf, and F-Star; consultant – Astellas, BMS, Almirall; research funding – BMS, Astellas, and Novasenta.
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