Furthermore, intracellular misfolded SOD1 was detected in the NP-40 soluble fraction from hSOD1WT and the ALS-linked hSOD1 mutant cells using a sandwich enzyme-linked immunosorbent assay (ELISA) with antibodies specific for misfolded SOD1 (Figure 1c). Here, SOD1 is linked to amyotrophic lateral sclerosis.