Although obesity is associated with a pro-inflammatory state (6), assessment of serum cytokine levels in DIO and CD mice on day 2 post-immunization showed no difference in levels of pro-inflammatory cytokines, IL-6 and TNF-α, or anti-inflammatory cytokine IL-10 (Supplemental Figures 5A–C). Here, IL6 is linked to obesity due to melanocortin 4 receptor deficiency.