Determination of tissue levels of IFN-γ
Spleens and lumbar spinal cords were collected following transcardiac perfusion and processed for the assessment of IFN-γ levels via enzyme-linked immunosorbent assay (ELISA). Tissue homogenates were prepared as described previously [13] and stored at −80°C until analysis. Levels of IFN-γ were determined with a Duo Set ELISA kit (R&D Systems, Minneapolis, MN) following the manufacturers’ protocol. The IFN-γ level of each sample was normalized based on the protein concentration of the particular sample as determined by the BCA protein assay (Pierce-Thermo Scientific, Rockford, IL).