Fig. 1.
Design of the GFP-tagged anti–5-HT2C fragment antigen binding protein (2C-Fab-GFP). (A) The Fab is composed of the heavy- and light-chain variable regions (VH and VL) of a monoclonal antibody raised against the 5-HT2C receptor and the constant regions (CH1 and CL) of antilysozyme D1.3 from pASK84. (B) The light-chain cDNA sequence was cloned into an expression vector with an internal ribosomal entry site (IRES) followed by an red fluorescent protein (RFP) selection marker. The heavy-chain cDNA sequence was cloned into an expression vector upstream and in frame with the cDNA sequence for GFP, for direct labeling of the heavy chain with a GFP tag. (C) 2C-Fab-GFP was purified from the culture media of a stable HEK293 cell line coexpressing the heavy- and light-chain plasmids. CMV, cytomegalovirus.