To clarify the biological significance of the interaction of the redox system (Prx2/GPx1) with SOD1 in SOD1-mutated motor neurons in vivo, we produced an affinity-purified rabbit antibody against Prx2 and investigated the immunohistochemical localization of Prx2 and GPx1 in neuronal Lewy body-like hyaline inclusions (LBHIs) in the spinal cords of familial amyotrophic lateral sclerosis (FALS) patients with a two-base pair deletion at codon 126 and an Ala-->Val substitution at codon 4 in the SOD1 gene, as well as in transgenic rats expressing human SOD1 with H46R and G93A mutations.