Immunohistochemistry is commonly distinguished as being the process of conducting immunoreactions on tissue thin sections, whereas immunocytochemistry is the same type of reactions on cell cultures. Furthermore, the term immunofluorescence is also often applied to immunochemical reactions that involve fluorophores conjugated to primary and secondary antibodies, as well as antibody fragments. In the scientific literature and the catalogs of antibody manufacturers, these terms are useful to segregate between products designed for cytological use and those targeted at paraffin or frozen tissue sections. However, the general principles of immunology are the same regardless of whether they are applied to isolated cells or those embedded within a tissue matrix.

In the digital image presented above, microtubules were stained using immunofluorescence by treating a fixed and permeabilized culture of MDCK cells with mouse-anti-alpha-tubulin primary antibodies followed by goat anti-mouse antibodies conjugated to Alexa Fluor 568. Nuclei were counterstained with SYTOX Green. Although not imaged in this section, the culture was also labeled with Alexa Fluor 350 conjugated to phalloidin. 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.