MOG-expressing CHO cells sequester NGF to control local concentrations of NGF to influence neuronal survival. (A) NGF-dependent dorsal root ganglion (DRG) neurons were plated into permeable transwell chambers and co-cultured with MOG-expressing CHO cells in the inserts, at varying concentrations of NGF. DRG neurons were analyzed for apoptosis using pSIVA (Kim et al., 2010) after 3 d in the presence of CHO cells; shown is the result at 50 ng/ml NGF. (B) Quantification of DRG survival at different NGF concentrations in the absence of CHO cells (control), in the presence of the CHO cells, and in the presence of CHO-MOG cells. Error bars represent SDs, and asterisks represent significance based on Student’s t test as compared with the control CHO cells (*, P < 0.05). (C) Coimmunoprecipitation of MOG after addition of NGF and chemical cross-linking. MOG-CHO and CHO cells were incubated with NGF at 500 ng/ml and 5 µg/ml and chemically cross-linked before coimmunoprecipitation with an anti-MOG antibody. Blots were also probed with an anti-NGF antibody to demonstrate direct association of NGF to MOG.