'Antigen masking' refers to the phenomenon where the epitopes (the specific binding sites recognized by antibodies) on tissue proteins become hidden or structurally altered during formalin fixation, rendering them inaccessible to antibodies. Formalin (a solution of formaldehyde) works as a fixative by creating methylene bridges (-CH2-) between adjacent amino groups on proteins. While this cross-linking preserves tissue architecture excellently, it also changes the three-dimensional conformation of proteins. This physical alteration can bury the specific epitope within the cross-linked protein meshwork or change its shape so that the antibody no longer recognizes it. The result is that an antigen known to be present in the tissue may not stain with its specific antibody. This is a major reason why antigen retrieval techniques (like heat or enzymatic digestion) are essential for IHC on formalin-fixed, paraffin-embedded (FFPE) tissues. These methods break some of the cross-links and 'unmask' the epitopes, allowing antibody binding.

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Zambia

• loveness Phiri – 1084 pts

• Visual Pathway Lesions
• Positive and Negative Symptoms
• Hallucinations and Delusions
• Antipsychotic Medications
• Emergency: Environmental Emergencies