The A-549 cell line was originally cultivated in 1972 by D. J. Giard, along with several collaborators, from the human lung carcinoma of a 58-year-old Caucasian male. The line is commonly used to investigate a wide range of respiratory ailments, such as viral infections capable of inducing asthma, tissue damage linked to asbestos exposure, and smoking-related emphysema. Adherent and epithelial, A-549 cells are positive for keratin by immunoperoxidase staining, but are negative for reverse transcriptase, indicating the lack of integral retrovirus genomes. Studies by a team led by M. Lieber have revealed that A-549 cells are able to synthesize lecithin with a high percentage of desaturated fatty acids utilizing the cytidine diphosphocholine pathway.

The adherent culture of human carcinoma (A-549) cells illustrated above was stained with Alexa Fluor 350 conjugated to wheat germ agglutinin for the Golgi apparatus, as well as Alexa Fluor 488 conjugated to phalloidin for cytoskeletal actin. Nuclei were labeled with the intercalating dye, propidium iodide. Images were recorded in grayscale with a QImaging Retiga Fast-EXi camera system coupled to an Olympus BX-51 microscope equipped with bandpass emission fluorescence filter optical blocks provided by Omega Optical. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.