Tissue immunofluorescence assay
Spleens and kidneys from WT and CCR2 KO mice were frozen in Tissue-Tek® O.C.T. embedding medium (Sakura Finetek, Torrance, CA, USA), and cut into 10 μm-thick cryosections, followed by fixation with ice-cold acetone for 5 min. Sections were incubated in 5% BSA (4240GR100, BioFroxx, Einhausen, Germany) containing 1% anti-CD16/CD32 mAb to block Fc receptors and then incubated with the primary Abs overnight at 4 °C. Next, sections were incubated with Dylight 650 (84547, Thermo Fisher) or AF488 G/R IgG (A11006, Thermo Fisher). Images were captured and analyzed using the NIS elements AR 5.01 software (Nikon).