Title: Eosinophilic granulocyte (peripheral blood, human)
Description: Electron microscopy.
A 11-15 mm cell with a partially cut bilobed nucleus (1) and moderate amount of organelles and vesicles. The specific eosinophilic granules (2) contain a central electron-dense angular crystalloid core (3) embedded in a finely granular matrix (4). The crystalloid consists of of an alkaline protein called major basic protein or MBP, the matrix contains eosinophil cationic protein or ECP, lysosomal enzymes such as myeloperoxidase, and lactoferrin. Occasionally smaller granules (azurophilic granules in light microscopy) might be present with a high content of acid phosphatase, arylsulfatase.
Background: These cells are considered phagocytic with a special affinity for antigen-antibody complexes. But their major function is to create the first line for defense against parasites. The MBP and ECP among others damage the parasite membrane. The eosinophils have FcE receptors for IgE.
Keywords/Mesh: blood, bone marrow, eosinophilic granulocyte, specific granule, phagocytosis, histology, electron microscopy, POJA collection