Transmission electron microscopy (TEM) uses a transmission electron microscope to form a two-dimensional image by shooting electrons through a thin piece of tissue. The brighter certain areas are on the image, the more electrons that are able to move through the specimen. Transmission Electron Microscopy has been used as a way to view immunolabeled tissues and cells. For instance, bacteria can be viewed by TEM when immunolabeling is applied. A study was conducted to examine the structures of CS3 and CS6 fimbriae in different "Escherichia coli" strains, which were detected by TEM followed by negative staining, and immunolabeling. More specifically, immunolabeling of the fimbriae confirmed the existence of different surface antigens.