Blood was collected via a retro-orbital bleeding technique from anti-B7x treated mice and IgG-treated control mice following an 18-h fast. Serum levels of insulin were measured by ELISA with the Ultrasensitive Mouse Insulin ELISA Kit (Mercodia, NC, USA) as described previously (Shen et al., 2009 (link)). The expression levels of IFN-γ and TNF-α in tumor tissues from B7x treated mice and IgG control mice were measured by a mouse IFN-γ ELISA kit (Abcam, MA, USA) and a mouse TNF-α ELISA kit (Life Technologies, MD, USA) following the manufacturer protocols.