SPON2 and diabetes mellitus: To further investigate Spondin-2 upregulation in the context of diabetes and TGFβ, we stimulated purified NK cells with IL-15 (10 ng/mL), with or without TGFβ (5 ng/mL) and in the presence of higher glucose concentrations (16 or 4 g/L relative to culture media) and measured Spondin-2 upregulation, or FcεR1γ upregulation as a positive control, at day 6.