Histology and immunohistology of DC subsets.

Magnification, × 20. (top panel) Hematoxylin and eosin. Cytokine therapy resulted in a mixed cellular infiltrate and distortion of normal follicle structure. (middle panel) CD11c (brown) and CD11b (blue) immunostain. Treatment with either GM alone or with GM/IL-4 resulted in enlarged and somewhat disorganized follicles (arrows). GM increased the number of CD11b⁺ and CD11c⁺ cells distributed throughout the white pulp (W) and marginal zones. GM/IL-4 preferentially increased the CD11c⁺ population with a marked localization to the white pulp. (bottom panel) DEC-205 (brown) and Igβ (blue) immunostain. Igβ identifies B cells and highlights the enlarged follicles in cytokine-treated mice. Control mice demonstrated light staining for DEC-205 within follicle centers. GM therapy was associated with an increase in DEC-205 staining, consistent with the increase in follicle size. In contrast, rGM/rIL-4 resulted in intense staining of tightly packed DEC-205⁺ cells within the centers of follicles.