Adaptive plasticity of IL10 + and IL35 + regulatory T cells

Regulatory T cells (T regs) maintain host self-tolerance but are a major barrier to effective cancer immunotherapy. T regs subvert beneficial anti-tumor immunity by modulating inhibitory receptor (IR) expression on tumor infiltrating lymphocytes (TILs); however, the underlying mediators and mechanisms remain elusive. Here we show that interleukin-10 (IL10) and interleukin-35 (IL35; Ebi3/IL12a heterodimer) are divergently expressed by T reg subpopulations in the tumor microenvironment (TME) and cooperatively promote intratumoral T cell exhaustion. T reg -restricted deletion of Il10 and/or Ebi3 resulted in delayed tumor growth, loss of multi-IR expression, and reduced intratumoral CD8 + T cell exhaustion signature. While Il10 or Ebi3 loss was associated with reduced expression of B lymphocyte-induced maturation protein-1 (BLIMP1; Prdm1), IL10 and IL35 differentially impacted effector versus memory T cell fates, respectively, highlighting their differential, partially overlapping but non-redundant regulation of anti-tumor immunity. Our results reveal previously unappreciated cooperative roles for IL10 and IL35, produced by limits effective anti-tumor immunity Overall design: TIL CD8 cells from Treg specific IL10, IL35 and double knockouts, sorted into populations based on exhaustion markers. TIL Tregs sorted based on IL10 and IL35 expression.

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Sawant DV, Yano H, Chikina M, Zhang Q, Liao M, Liu C, Callahan DJ, Sun Z, Sun T, Tabib T, Pennathur A, Corry DB, Luketich JD, Lafyatis R, Chen W, Poholek AC, Bruno TC, Workman CJ, Vignali DAA