The tissue fragments were collected with 4-mm punch and fixed in formalin 10%, pH 7·2, and processed by the usual techniques for optical microscopy. At 4th and 8th weeks PI, biopsies from the hind footpads were collected, soaked in OCT medium (Easy Path, Brazil), and immediately frozen in liquid nitrogen. The fragments were stored in freezer at −80°C. Sections from skin were prepared using a cryostat microtome (Leica

Microsystems, Wetzlar, Germany), and fixed in acetone–chloroform (1 : 1) for 10 min at room temperature. After washing in PBS (for 10 min), the endogenous peroxidase and nonspecific binding were blocked with a solution of hydrogen peroxidase 0·3% (10 min) and skimmed milk 6% (1 h),

respectively. Fragments of PF-02341066 cell line skin were Dabrafenib concentration incubated overnight with monoclonal antibodies rat anti-mouse CD207 (BD Bioscience, San Diego, CA, USA) at 1 : 100, CD4 and CD8α (BD Pharmingen, San Diego, CA, USA) at 1 : 160 and 1 : 40, respectively, and hamster anti-mouse CD11c (BD Pharmingen) at 1 : 10 dilution in PBS plus 1% BSA. The biotinylated secondary antibody goat anti-rat immunoglobulin (BD Pharmingen), at 1 : 50 dilution, incubated for 1 h at 37°C was used for CD4, CD8, and CD207, and mouse anti-hamster IgG cocktail (BD Pharmingen) at 1 : 50 dilution for CD11c. The sections were incubated with streptavidin–HRP (Dako, Carpinteria, CA, USA) for 45 min at 37°C. Afterwards, the sections were incubated with diaminobenzidine solution from Liquid DAB+Substrate Chromogen System (Dako) for 5–10 min. The sections were counterstained with Harris Hematoxylin, and the slides were mounted using cover slides and

resin. For quantitative analysis, ten different fields of each section were photographed, and the cell numbers were evaluated with a Carl Zeiss microscope coupled to a computer using the axion vision 5·0 software (Axion Vision, Carl Zeiss Microscopy GmbH, Munich, Germany). The cellular densities were expressed by cells per square millimetre. The paraffin-embedded skin sections were dewaxed and rehydrated, and the antigen retrieval why was performed by steaming in 10 mm citric acid solution (pH 6·0) for 30 min at 95°C in a water bath. Endogenous peroxidase activity was blocked with 3% hydrogen peroxide and nonspecific interactions with a solution of 6% powdered skimmed milk solution. The reaction was developed using, as a primary antibody, rabbit anti-NOS2 polyclonal antibody (Santa Cruz Biotechnology, Santa Cruz, CA, USA) at 1 : 1000 dilution in PBS plus 1% BSA and, as a detection system, NovoLink Max Polymer (Novocastra, Newcastle Upon Tyne, United Kingdom). The sections were counterstained with Harris Hematoxylin, and the slides were mounted using cover slides and resin.