suppress cytokine secretion, antigen presentation and CD4+ T cell activation. Further investigation has shown that IL-10 predominantly inhibits lipopolysaccharide (LPS) and bacterial product mediated induction of the pro-inflammatory cytokines TNFα, IL-1β, IL-12, and IFNγ secretion from Toll-Like Receptor (TLR) triggered myeloid lineage cells. Effect on tumors Over time a more nuanced picture of IL-10's function has emerged as treatment of tumor bearing mice has been shown to inhibit tumor metastasis. Additional investigation by multiple laboratories has generated data that further supports IL-10's immunostimulatory capacity in an immunoncology context. Expression of IL-10 from transfected tumor cell lines in IL-10 transgenic mice or dosing with IL-10 leads to control of primary tumor growth and decreased metastatic burden. More recently, PEGylated recombinant murine IL-10 (PEG-rMuIL-10) has been shown to induce IFNγ and CD8+ T cell dependent anti-tumor immunity. More specifically, PEGylated recombinant human IL-10 (PEG-rHuIL-10) has been shown to enhance CD8+ T cell secretion of the cytotoxic molecules Granzyme B and Perforin and potentiate T cell receptor dependent IFNγ secretion. Role in disease A study in mice has shown that IL-10 is also produced by mast cells, counteracting the inflammatory effect that these cells have at the site of an allergic reaction. IL-10 is capable of inhibiting synthesis of pro-inflammatory cytokines such as IFN-γ, IL-2, IL-3, TNFα and GM-CSF made by cells such as macrophages and Th1 T cells. It also displays a potent ability to suppress the antigen-presentation capacity of antigen presenting cells; however, it is also stimulatory towards certain T cells (Th2) and mast cells and stimulates B cell maturation and antibody production. IL-10 checks the inducible form of Cyclo-oxygenase, Cyclo-oxygenase-2 (COX-2). Lack of IL-10 has been shown to cause COX activation and resultant Thromboxane receptor activation to cause vascular endothelial and cardiac dysfunctions in mice. Interleukin 10 knockout frail mice develop cardiac and vascular dysfunction with increased age. IL-10 is linked to the myokines, as exercise provokes an increase in circulating levels of IL-1ra, IL-10, and sTNF-R, suggesting that physical exercise fosters an environment of anti-inflammatory cytokines. Lower levels of IL-10 have been observed in individuals diagnosed with multiple sclerosis when compared to healthy individuals. Due to a decrease in IL-10 levels, TNFα levels are not regulated effectively as IL-10 regulates the TNF-α-converting enzyme. As a result, TNFα levels rise and result in inflammation. TNFα itself induces demyelination of the oligodendroglial via TNF receptor 1, while chronic inflammation has been