Significantly increased lectin-positive cells at the early stage of disease. (A) Lumbar sections of spinal cord from mSOD1/RAG2-/- and mSOD1/RAG2+/+ mice at early (70-90 days of age) and end (130-150 days of age) stage of disease were stained for lectin (microglia/macrophage). Scale bar = 50 μm. (B) Significantly increased numbers of lectin-positive microglia/macrophages are observed at the early stage of the disease in spinal cord sections of mSOD1/RAG2-/- mice compared with mSOD1/RAG2+/+ mice. There was no significant difference in the number of lectin-positive cells at the end stage of disease. Significance was evaluated by using a generalized Wilcoxon test. **: p < 0.01. (C) Western blot analysis of Iba-1 shows markedly increased expression in lumbar spinal cord of mSOD1/RAG2-/- mice compared with mSOD1/RAG2+/+ mice at early stage. Data presented in A-C is representative of three animals.