Immunohistochemistry Stains

Immunohistochemistry (IHC) staining involves using dyes, substrates, and specific antibodies to visualize the presence and localization of specific antigens in tissue sections in concert with histological staining. Stains like hematoxylin are often used to counterstain nuclei, contrasting with antibody-mediated signals or fluorescent dyes. Applications of IHC staining in research are broad, including cancer diagnostics, mapping tissue-specific protein expression, studying disease biomarkers, and analyzing immune responses. Additionally, dual or multiplex staining enables the simultaneous detection of multiple antigens, offering insights into cellular interactions. IHC stains that are commonly used in research are highlighted below.

Notable Immunohistochemistry stains

• Hematoxylin - This stain is component of the widely used hematoxylin and eosin (H&E) staining method. The hematoxylin dye binds to negatively charged molecules such as DNA to produce a blue or purple hue.
• Eosin - This stain stains cytoplasmic components, extracellular structures, and connective tissues with a pink to red color. Hematoxylin and eosin (H&E) staining is a widely used histological method to differentiate cellular and tissue structures.
• Alcian Blue - This water-soluble dye, which stains acidic polysaccharides, is often used in histochemical staining to identify mucins, cartilage, and connective tissues.
• Azure B - This dye stains nucleic acid and polysaccharide and is a component of Wright's and Giemsa stains, used in the visualizing blood cells and detecting parasites.
• Congo Red - This pH-sensitive dye is often used to stain amyloid deposits, cellulose, and polysaccharides. It can also act as an indicator, changing from red in basic conditions to blue in acidic environments.
• Cresyl Violet - This synthetic dye is often used to highlight neuronal cell bodies, such as in the staining of Nissl bodies in motor neurons of the spinal cord and brainstem.
• Giemsa Stain - A versatile stain used in histology and cytology to highlight nuclei, cytoplasm, and chromatin structures, commonly for blood smears and parasite identification.
• Fuchsine - A magenta-colored dye commonly used for staining collagen, connective tissues, and microbial identification by Gram staining.
• Safranin - A red cationic dye used to stain nuclei, cartilage, and bacteria via Gram staining.
• Prussian Blue - A histochemical reaction stain specific for detecting ferric iron deposits, creating a distinctive blue pigment.
• Methyl Green - A cationic dye that selectively binds AT-rich regions of native DNA, making it useful for staining nuclear and chromatin structures.
• Oil Red O - A lipid-soluble dye that stains neutral lipids and triglycerides, widely used in metabolic and lipid storage studies.
• Orange G - This acidic dye stains the cytoplasm and keratin a bright orange, making it useful in in histological trichrome and multicolor staining techniques.

Considerations for choosing IHC stains

When choosing IHC stains, researchers should consider factors like tissue type, antigen stability, the sensitivity of detection methods, and the compatibility of the stain with the primary antibody and detection system. Signal clarity, background reduction, and resistance to fading are also important in producing quality images. The imaging method (light vs. fluorescence microscopy) is another defining aspect, as only certain dyes will exhibit fluorescence. Refer to supplier product datasheets for useful information, such as product specifications, usage recommendations, literature citations, validation information, and experimental images.