Fig. 1

Age- and sex-dependent changes in body and spleen weight. a Graph represents body weight (BW) (g). b Graph represents spleen weight (g). c Graph represents ratio of spleen weight (g) to BW (g). d Graph represents total number of splenocytes. e Graph represents number of splenocytes per gram of spleen. Males are represented by blue circles and females are represented by pink squares. Young males (n = 8–12, 2–3 months); young females (n = 5–13, 2–3 months); aged males (n = 11, 18–22 months); aged females (n = 11, 18–22 months). Data were analyzed by 2-way ANOVA followed by Fisher’s LSD post hoc analysis. Data represent mean ± SEM. Comparisons within sex: *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. Comparisons within age: #p < 0.05, ##p < 0.01, ###p < 0.001, ####p < 0.0001