Monitoring expression of TNFR2 with anti-TNFR2 single-chain variable fragment (ScFv). (a) Immunoprecipitation of His-tagged tumour necrosis factor types 1 and 2 (TNFR1 and TNFR2) with anti-His antibody (left panel), and anti-TNFR2 single-chain variable fragment (ScFv) (right panel). The ScFv precipitated TNFR2, at ~75 KDa, but not TNFR1, at ~55 KDa, while the anti-His antibody precipitated both receptors, indicating specificity of the ScFv. Double immunohistochemistry against TNFR2-transfected 293T cells with anti-His antibody (b), and ScFv plus anti-myc-CY-3 (c) indicates that the selected ScFv specifically binds toTNFR2. (d) Immunohistochemistry with anti-TNFR2 ScFv in the dorsal root ganglion 7 days after inflammation ipsilateral to injection. TNFR2 colocalisation was observed with the macrophage marker, ED1 (e) but not with glial fibrillary acidic protein (GFAP) (f), indicating expression of TNFR2 by macrophages following inflammation.