Figure 2. The metabolic improvements by calorie restriction in aging are mediated through reducing IgG.

(A-E) 12-month-old male C57BL/6J mice were subjected to 30% caloric restriction (CR) for 4 weeks. (A-B) WB of plasma IgG, IgA, and IgM levels in ad libitum (ad lib) and CR mice (A) and quantifications (B). ***p<0.001 for CR vs ad lib control by 2-tailed student t-test (n=6, 6).

(C-D) WB analysis (C) and quantification (D) of IgG and SirT1 in protein lysates of eWAT and iWAT from ad lib and CR mice. HSP90 was used as the loading control, (n=6, 6).

(E) qPCR analysis of gene expression (arbitrary units, AU) in eWAT of a different cohort of 4-week CR and ad lib mice (n=8, 8).

(F-H) 5-month-old male C57BL/6J mice were intraperitoneally (i.p.) administered 3 mg mouse total IgG or vehicle (Veh) per week for 4 weeks since the beginning of CR. The regularly fed mice were included as the ad libitum control group.

(F) WB analysis of IgG in eWAT from mice treated with ad lib, CR-Veh and CR-IgG.

(G) qPCR analysis of eWAT gene expression from all three groups of mice (n=5, 8, 7).

(H) Insulin tolerance test (ITT) and the area under curve (AUC) after 3-wk treatment (n=5, 8, 7).

Data are presented as mean ± SEM; *p<0.05, **p<0.01 vs CR-Veh group by 2-tailed student t-test or one-way ANOVA.

See also Figure S3.