The immune system employs two distinct defense strategies against infections: pathogen elimination typified by type 1 immunity, and pathogen containment exemplified by type 2 immunity in association with tissue repair. Akin to infectious diseases, cancer progresses with cancer cell acquisition of microorganism-like behavior propagating at the expense of the host.While immunological mechanisms of cancer cell elimination are well defined, whether immunemediated cancer cell containment can be induced is poorly understood. Here we show that ablation of transforming growth factor-β receptor II (TGFβRII) in CD4 + T cells promotes tumor tissue healing and halts cancer progression. Notably, the restorative response is dependent on the T helper 2 cytokine IL-4 fortifying vasculature organization that spares only proximal layers of cancer cells from hypoxia, nutrient starvation and death. Thus, type 2 immunity represents an effective cancer defense mechanism, and TGFβ signaling in helper T cells may be targeted for novel cancer immunotherapy.3
TextIn response to invading pathogens, vertebrate immune system employs two discrete strategies of host defense: pathogen elimination typified by type 1 immunity following innate immune recognition of prokaryotic microorganisms 1 , and pathogen containment associated with tissue repair manifested by type 2 immunity following the invasion of metazoan parasites that inflict tissue damage 2 . Similar to infectious diseases, cancer imposes insults to the host with cancer cell acquisition of microorganism-like behavior of clonal expansion. Indeed, cancer cell-targeted type 1 immunity mediated by CD8 + cytotoxic T lymphocytes (CTLs), cytotoxic innate lymphocytes and innate-like T cells represent host protective mechanisms of cancer cell elimination 3-5 . Notwithstanding, the host impact of cancer cells is much more intimate than that of microbes, and cancer pathogenicity, in particular that of solid tumors, is dependent on cancer cell coercing a supportive environment that promotes tumor encroachments leading to the impairment of tissue function [6][7][8][9] . Notably, tumor tissues resemble active wounds, and are considered as "wounds that do not heal" 10 , implying that cancer microenvironment-targeted tissue repair responses could restrain tumor progression.Dissimilar from infectious diseases, cancer arises from malignant transformation of selfcells. Consequently, immunological self-tolerance can be maladapted to repress cancer-elicited immune responses. Indeed, multiple T cell self-tolerance regulators including Foxp3 + regulatory T (Treg) cells, co-inhibitory receptors PD-1 and CTLA-4, and the regulatory cytokine transforming growth factor-β (TGFβ) suppress immune control of tumor development [11][12][13][14][15] .Depletion of tumor-infiltrating Treg cells via genetic approaches or administration of anti-PD-1 and anti-CTLA-4 result in CTL-dependent cancer cell elimination in animal models and patients 16,17 . In transgenic mouse models of cancer, blockade of TGFβ signaling in T cells...