Polyclonal antibodies against the extracellular (Millipore Cat# AB1554 RRID:AB_90760) and cytoplasmic (Promega Cat# G3231 RRID:AB_430853) domains of the low-affinity neurotrophin receptor p75NTR (both at 1:400 dilution) were used to identify Schwann cells in vitro (Provenzano et al., 2011 (link); Whitlon et al., 2009 (link)), determine their specific location within synapse cultures, and their alignment to neighboring spiral ganglion neurons. Western blot and immunocytochemical analysis of antibody specificity showed the expected lack of protein in p75NTR−/− animals compared to wild type controls (Gehler et al., 2004 (link); Shulga et al., 2012 (link); Wagner et al., 2011 (link)).