Sections for immunofluorescence are typically prepared on which instrument?

• A. Microtome
• B. Cryostat
• C. Electron microscope
• D. Ultramicrotome

Answer: (B)

Preserving antigenicity for antibody binding is best achieved with frozen tissue sections, which are prepared in a cryostat. A cryostat is a microtome kept at low temperatures inside a refrigerated chamber, allowing thin sections (about 4–6 μm) of fresh or rapidly frozen tissue to be cut and mounted on slides without the denaturation that can occur during routine paraffin processing. This rapid freezing preserves epitopes, making immunofluorescent labeling more reliable.

In contrast, a microtome cuts paraffin-embedded tissue after wax infiltration, which requires deparaffinization and can mask or alter epitopes; ultramicrotomes are for ultrathin sections used in electron microscopy, not standard immunofluorescence; another instrument like an electron microscope is used for imaging, not for preparing IF slides.