Immunohistochemical assessment of immune cells in mouse tumor tissue

This protocol describes a procedure for the evaluation of immune cells at the histological level. This technique preserves tissue architecture, making use of tissues that have been frozen in optimal cutting temperature (OCT) medium immediately after dissection and then cut with a cryostat into thin (∼8 µm) sections. The tissue slices are transferred to microscope slides and, as described here, are fixed with either methanol or formaldehyde. The fixed tissue sections are then stained with antibodies directed against cell surface markers expressed by the immune cells of interest. The antibodies are detected with an avidin-biotin-based peroxidase system, and, after mounting, the sections can be stored and viewed for years.