African Green Monkey Kidney Cellular Keratin Network

B-1E Bandpass Emission (Narrow Bandwidth Excitation) Blue Set

Fluorescence emission intensity from a culture of African green monkey (COS-1 line) cells that were immunofluorescently labeled with primary anti-cytokeratin mouse monoclonal antibodies followed by goat anti-mouse F(ab')2 fragments conjugated to biotin. The secondary antibody was subsequently stained with quantum dots (QDot 525) conjugated to streptavidin and counterstained with DAPI for DNA in the nucleus. In COS-1 cells, the keratin protein network is not as organized and clearly defined as is observed with other cell types. Excitation of QDot 525 conjugates is most efficiently conducted in the ultraviolet, but green fluorescence at 525 nanometers can still be detected when the probe is illuminated with blue wavelengths (470-490 nanometers) by the B-1E filter combination. Note the absence of signal from the blue DAPI fluorophore in this specimen, but the relatively bright green fluorescence exhibited by the labeled keratin network.