Xie, Yu-QingArik, HacerWei, LixiaZheng, YiranSuh, HeikyungIrvine, Darrell J.Tang, Li2019-06-182019-06-182019-06-182019-04-0110.1039/c8bm01556bhttps://infoscience.epfl.ch/handle/20.500.14299/157443WOS:000463746600008Interleukin-2 (IL-2) is a potent T-cell mitogen that can adjuvant anti-cancer adoptive T-cell transfer (ACT) immunotherapy by promoting T-cell engraftment. However, the clinical applications of IL-2 in combination with ACT are greatly hindered by the severe adverse effects such as vascular leak syndrome (VLS). Here, we developed a synthetic delivery strategy for IL-2 via backpacking redox-responsive IL-2/Fc nanogels (NGs) to the plasma membrane of adoptively transferred T-cells. The NGs prepared by traceless chemical cross-linking of cytokine proteins selectively released the cargos in response to T-cell receptor activation upon antigen recognition in tumors. We found that IL-2/Fc delivered by T-cell surface-bound NGs expanded transferred tumor-reactive T-cells 80-fold more than the free IL-2/Fc of an equivalent dose administered systemically and showed no effects on tumor-infiltrating regulatory T-cell expansion. Intriguingly, IL-2/Fc NG backpacks that facilitated a sustained and slow release of IL-2/Fc also promoted the CD8(+) memory precursor differentiation and induced less T-cell exhaustion in vitro compared to free IL-2/Fc. The controlled responsive delivery of IL-2/Fc enabled the safe administration of repeated doses of the stimulant cytokine with no overt toxicity and improved efficacy against melanoma metastases in a mice model.Materials Science, BiomaterialsMaterials Scienceinfiltrating lymphocytesreceptoril-2immunotherapymelanomaexpansiontherapygenetext::journal::journal article::research article