Figure 7.

Production of CCL19 and CCL21 and expression of CCR7 by DCs in the granulomatous lesions. Two-color immunohistochemistry of frozen sections of temporal arteries from patients with GCA was used to identify the cellular source of CCL19 and CCL21. Top: Tissue sections were stained with anti-CCL21 (A), anti-CCL19 (C), and anti-CCR7 (E) Abs. Antibody binding was detected with Vector Blue. Bottom: DCs were identified with anti-CD83 Ab and Vector Red. Serial tissue sections were used to stain for CCL21 (A)- and CCL19 (C)-producing cells, which demonstrated that both chemokines derived from the same cell population. CCR7 (E) was exclusively found on CD83⁺ DCs (F), whereas tissue-infiltrating T cells were negative for this chemokine receptor. Original magnifications, ×400.