50ng of Human Kappa Chain (Lane 2) and 50ng of Human Lambda Chain (Lane 3) was run on a 4-20% gel and transferred to 0. 45 um nitrocellulose. After blocking with 1% BSA-TTBS blocking buffer for 30 min at 20 deg C, Goat anti-Human Kappa chain (FITC) F(ab’)2 secondary antibody was used at 1:1000 in blocking buffer.