2.1. Animals

Homozygous Tet2^fl/fl mice [21] were crossed with LysM^Cre mice [22] (Jackson Laboratory, Bar Harbor, ME) to generate myeloid cell-specific Tet2 deficient (Tet2^fl/flLysM^Cre) mice. Tet2^fl/fl Cre-negative littermates (Tet2^fl/fl mice) were used as controls in all experiments. LysM^Cre mice have been widely used for the elimination of genes in bone marrow-derived macrophages (BMDMs) and tissue-resident macrophages, including alveolar macrophages (AMs) and peritoneal macrophages (PMs) [23,24]. Tet2^fl/flLysM^Cre mice have an unaltered cellular composition of blood and spleen when compared with control mice and unlike global Tet2-knockout mice are not prone to develop pre-leukemic myeloproliferation [19]. All genetically modified mice were backcrossed at least eight times to a C57Bl/6 background and age and sex matched when used in experiments. Mice were used at 8–12 weeks of age.