Homing of lymphocytes is impaired in the mLN during M.tb infection.

(A) Experimental design. Splenocytes from tdTomato-expressing mice were injected i.v. into 3wk M.tb-infected WT mice. The iLN and mLN were analyzed 2 h post-transfer. (B) Total cell number of iLN and mLN as well as percentage and number of donor tdTtomato+ lymphocytes (2 h post cell transfer) in iLN and mLN at wk 3 p.i. (C) Representative staining of MECA-79 (yellow) in iLN and mLN at wk3 p.i. Scale bar 100 μm. Enlarged view of the boxed area in the left images are shown in right panels. Enlarged view representing stained HEV with MECA-79 (yellow) and CD31 (red) (Scale bar, 50 μm). Number of HEV/mm2 measured in naïve mLN as well as infected iLN and mLN. (D) Representative staining of CCL21 (magenta) and CD31 (green) in iLN and mLN at wk 3 p.i. (E) Percentage of HEV in CCL21 region in iLN and mLN at wk 3 p.i. Each symbol represents an individual mouse in (B) and sections in (C, D). Data in (B) are pooled from two independent experiments. Data in (C) are from two independent experiments (n = 4–6 mice / group, 1–2 sections / mouse were analyzed). Data in (D-E) are from two independent experiments (n = 3 mice / group, 1–2 sections / mouse were analyzed) Statistical differences between groups in (B, E) were determined using Student’s t test or in (C) using one-way ANOVA with Tukey’s multiple comparison test. ** p p p < 0.0001.