Anti-GFP Antibody - Western Blot. Western blot of GFP protein detected with polyclonal anti-GFP antibody. Lane 1 shows negative control staining of 20 ug of mouse spleen lysate. Lane 2 shows staining of mouse spleen lysate spiked with 50 ng of wt GFP. This antibody detects a 27 kD band corresponding to the GFP epitope tag commonly used in recombinant constructs. A 4-20% Tris-Glycine gradient gel was used for SDS-PAGE followed by transfer to nitrocellulose using standard methods. After blocking with 5% BSA in PBS, the membrane was probed for 2 h at room temperature with the primary antibody diluted in 5% BSA to 2 ug/ml, followed by washes and reaction with a 1:20000 dilution of IRDye800 Conjugated Affinity Purified anti-Chicken IgG [H&L] [Goat] MX10 (. The IRDye 800 fluorescence image was captured using the Odyssey Infrared Imaging System developed by LI-COR. IRDye is a trademark of LI-COR, Inc. Other detection systems will yield similar results.