Jα18 KO mice are more susceptible to body weight gain and adipose tissue inflammation upon HFD. Eight-week-old WT and Jα18 KO mice were fed NCD or HFD for 4 weeks. (A) Body weight gain was measured every week. (B) Absolute body weight after 4 weeks of HFD; (C) fat mass (grams); (D) plasma insulin levels (ng/ml). (E) Mice were given HFD for 4 weeks and then subjected to the oral glucose tolerance test; n = 4 mice at each time point. *, P < 0.05, HFD WT versus HFD KO. (F) Percentage of CD11b+ F4/80+ and CD11b+ F4/80+CD11c+ cells among adipose tissue SVCs. **, P < 0.01, HFD WT versus HFD KO. (G) Numbers of CD11b+ F4/80+ and CD11b+ F4/80+CD11c+ cells per gram of fat mass. *, P < 0.05, HFD WT versus HFD KO. (H) Percentages of CD11c+ and CD206+ cells among CD11b+ F4/80+ cells in adipose tissue. *, P < 0.05, HFD WT versus HFD KO.