Activity of the Li81 secondary binding site mutants in the OPC differentiation and coculture assays. In A and B, samples were evaluated in the OPC differentiation bioassay using expression of MBP as a readout for differentiation. MBP expression was quantified by ICC and recorded as MFI per differentiated oligodendrocyte (Olig2+ cell). (a) Dose-response of Li81, CN1373, and CN1375 in the OPC differentiation assay. Data shown are from 2 independent studies. (b) Activity of Li81, LINGO-1, CN1373, and premixed CN1373/LINGO-1 complex in the OPC differentiation assay. C. DRG neuron/A2B5+ cell cocultures were treated with 3 µg/mL of Li81, CN1373, or 5C8 isotype control antibody. The cultures were fixed on day 10 and visually analyzed for axonal myelination by oligodendrocytes by ICC using anti-MBP (green, 488) and anti-tubulin (red, 594) antibodies for detection of myelinating oligodendrocytes and neurons, respectively.