Figure 2.

Spermidine Restores B Cell Responses in Old Mice

(A) Representative plot of LC3-II staining of B cells (CD19⁺) from Figure 1A.

(B) Autophagy (LC3-II) of purified B cells from wild-type mice (treated as in Figure 1A) was assessed using western blot. n = 6 or 7 mice.

(C) Old GFP-LC3 transgenic mice were administered spermidine as in Figure 1A. The GFP-LC3 puncta of purified B cells were measured using confocal microscopy. N = 210–616 cells from four to six mice.

(D) Young or old mice were immunized with NP-CGG and administered spermidine throughout the experiment. Serum NP-specific IgG1 titers were measured using ELISA. n = 14 (young) or 10 (old/old + spd) mice from two experiments.

(E) B cell-specific Atg7-KO mice (Mb1-Cre, Atg7^f/f) were immunized and IgG1 responses assessed as in (D). n = 7 (B-Atg7^+/+) or n = 3 (B-Atg7^−/−) mice.

(F) Mice from (D) were culled on day 75, and bone marrow plasma cells secreting NP-specific IgG1 were measured using ELISpot. n = 6–9 mice.

Data are represented as mean ± SEM. Paired one-tailed Student’s t test (B). Mann-Whitney test (C). Welch’s t test (D–F). p values were adjusted using the Holm-Sidak method for multiple comparisons of the three time points in (D) and (E). ^∗p ≤ 0.05, ^∗∗p ≤ 0.01, ^∗∗∗p ≤ 0.001, and ^∗∗∗∗p ≤ 0.0001.

See also Figure S2.