Figure 2.

Rhythmic Lymphocyte Homing Is Dependent on Oscillations in Both Lymphocytes and Microenvironment

(A) Lymph node homing of lymphocyte populations over the course of the day, normalized to peak times; n = 3–17 mice, one-way ANOVA.

(B) Adoptive transfer of lymphocyte populations using donor and recipient mice kept at ZT5 or ZT13; n = 6–17 mice, one-way ANOVA with Tukey’s multiple comparisons test.

(C) Oscillations of CCR7 surface expression on lymphocyte subpopulations in LN; n = 3–5 mice, one-way ANOVA.

(D) Q-PCR analysis of LN Ccl21 amounts over 24 hr; n = 3–5 mice, one-way ANOVA.

(E) Quantification and images of expression of CCL21 on HEV over 24 hr in constant darkness (CT, circadian time: the corresponding light and dark phase are indicated); n = 3–18 mice, one-way ANOVA. Scale bar represents 50 μm.

(F) LN homing of lymphocytes harvested at ZT5 or ZT13 and treated with or without pertussis toxin (PTX); n = 5–11 mice, one-way ANOVA with Tukey’s multiple comparisons test.

(G) Lack of oscillations in LN cellularity of Ccr7^−/− mice; n = 4 mice, unpaired Student’s t test.

(H) Lack of rhythmic LN homing of Ccr7^−/− cells into WT hosts; n = 5–6 mice, unpaired Student’s t test. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001, ^∗∗∗∗p < 0.0001. All data are represented as mean ± SEM. See also Figure S2.