Cellular makeup of infiltrates. Animals were sacrificed at day 24 after immunization, and spinal cord inflammation was assessed by flow cytometry. Infiltrates were stained with antibodies against CD45, CD11b, CD4, CD8, and GR-1 as described in Methods. Gate statistics are expressed as percentages as follows (WT:p35^–/–): R1 (lymphocyte gate CD45^hi/CD11b^–) = 28%:39%; R2 (macrophage/granulocyte gate CD45^hi/CD11b⁺) = 8%:10%; R3 (microglia gate CD45^lo/CD11b⁺) = 30%:25%.