embedded in paraffin. Tissue sections were stained with periodic acid schiff
(PAS) and analyzed by light microscopy. The nephritis scoring system was adapted
from the International Society of Nephrology/Renal Pathology Society (ISN/RPS)
classification of human lupus nephritis. At least 40 glomeruli per mouse were
evaluated. The final score accounted for morphological pattern (mesangial,
capillary, membranous) and for the percentage of involved glomeruli.
Immunofluorescence analysis on frozen kidney sections was performed by staining
with FITC-labeled goat anti–mouse IgG (Jackson ImmunoResearch
Laboratories) and specimens were analyzed with a LSM 510 laser scanning confocal
microscope (Carl Zeiss, Inc.). Images were captured by Q capture software. Five
representative glomeruli per mouse were chosen and mean fluorescent intensity
(MFI) was calculated using ImageJ software.