B-1a cells play a protective role against glucose intolerance. A: Frequency of CD19+ B-cell subpopulations in the PerC (left panel), VAT (middle panel), and spleen (right panel) from C57BL/6J mice fed the NCD or HFD for 9 weeks (n = 5, representative of three experiments). B: Absolute cell counts of B-cell subpopulations of mice fed the NCD or HFD (n = 5). Body weights (C), GTT with AUC analysis (D), ITT (E), and fasting insulin levels (F) of HFD Bnull recipients, 1 week after receiving PBS, B-1a, or B-2 cells (n = 5). G: IL-10 concentration in 24-h PerC culture supernatant (n = 5). H: Serum IgM concentration (n = 5). Values are given as mean ± SEM. *P < 0.05; **P < 0.005; ***P < 0.0005.