Morphofunctional study of the hemocytes of Haliotis asinina

The hemocytes of abalone (Haliotis asinina) were studied by light and electron microscopy in order to describe their main morphological features and to relate these to their role in immune defense. The cells are comprised of two differentiated types: agranulocyte or hyalinocyte and granulocyte. The hyalinocyte is characterized by the presence of several filopodia, a large nucleus with dense chromatin, a moderate amount of cytoplasm, microfilaments, oval and round-shaped mitochondria with rather dense matrix, a considerable amount of rough endoplasmic reticulum, few cytoplasmic granules, coated pits and vesicles, phagocytic vacuoles, and numerous large and small vacuoles. Like the hyalinocyte, the granulocyte possesses similar cytoplasmic organelles but in fewer number, and a peripheral organelle-free zone containing numerous dense granules of various types. The shape of the granules varies from round to oval to elongated forms. Several dense granules exhibit a crystalloid substructure that show close relationship to the plasma membrane. The average size of granulocytes is 9.68 plus or minus 1.12 mu m and hyalinocytes is 8.65 plus or minus 0.77 mu m.