
Immunoelectron microscopy using an antigen-antibody reaction in an electron microscope is a very useful tool to identify the components of a tissue in an electron microscope. Many researchers also use immunoelectron microscopy. Nonetheless, immunoelectron microscopy is rarely introduced systematically, and immunoelectron microscopy can be carried out without fully understanding the principles, and cases of poor understanding can often be seen in the vicinity. Therefore, in order to make it easier to understand, we will first introduce the principles of immunoelectron microscopy and describe practical methods.
![]() | Fig. 1. Structure of the immunoglobulin G molecule.
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![]() | Fig. 2. Comparison of pre-embedding and post-embedding.
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![]() | Fig. 3. Immunolabelling was performed with a primary antibody: Chemicon MAB922 & secondary antibody: Gold-conjugated (15 nm) protein A (supplied by Prof. Su Jin Kim), and then refinement & osmication and routine processing for scanning electron microscope (SEM), freeze drying and observed by field emission SEM (S-4700; Hitachi). The white spots in the picture are 15 nm gold. In the transmission electron microscope, the gold particles appear black because they interfere with the transmission of electrons ().
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![]() | Fig. 4. Electron micrographs showing osteopontin-labeled mitochondria (arrows) using immunoperoxidase electron microscopy in the 3-nitropropionic acid-injured lesion core in rat brain. Scale bar=1 μm.
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![]() | Fig. 5. (A, B) Electron micrograph showing nestin-positive cell associated with capillaries at 3 days post-ischemia by using immunogold/silver electron microscopy. Higher magnification (B) of the boxed area in Fig. 5A shows the silver grains (arrow) were exclusively localized along the bundles of intermediate filaments. Scale bars=2 μm (A), 0.4 μm (B).
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![]() | Fig. 6. (7) Post-embedding immunoelectron micrograph of neurofascin in 14 days old rat sciatic nerve. Unmyelinated fiber (UM) expresses neurofascin strongly in the axolemma (arrowheads), but myelinated fiber (M) doesn’t express neurofascin in the axolemma at all. SC, Schwann cell cytoplasm. Scale bar=200 nm. (8) Neurofascin immunoreactive gold particles are labeled in the outer mesaxon (arrowheads). My, compact myelin sheath. Scale bar=200 nm. (9) Node (N) and paranodal loops (PL) are shown. Many neurofascin immunoreactive gold particles are localized in the nodal axolemma (arrows). Neurofascin expression was revealed in the paranodal loops as well. Scale bar=500 nm. (10) Post-embedding immunoelectron micrograph of neurofascin in 5 days old rat sciatic nerve. Neurofascin immunoreactive gold particles are labeled in the inner mesaxon (arrowhead). Scale bar=200 nm. (11) Post-embedding immunoelectron micrograph of neurofascin in 14 days old rat sciatic nerve. Neurofascin immunoreactive gold particles are labeled in the Schmidt-Lantermann incisures (arrowheads). Scale bar=200 nm. (12) Non-compact myelin layer which in composed of apposing Schwann cell membranes expresses neurofascin immunoreactivity (arrowheads), but compact myelin layer doesn’t express neurofascin at all. Scale bar=200 nm. Adapted from the article of ( |
![]() | Fig. 7. (A) Confocal microscopic double-labeled image with osteopontin and mitochondria marker NDUFV2. Higher magnification the boxed area in Fig. 7A show the corresponding transmission electron microscopic image obtained from the same field in the 3-nitropropionic acid (3NP)-injured lesion core (B–D). Scale bars=5 μm (A), 10 μm (B–D).
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