An ultrastructural study of human eosinophil granules: maturational stages and pyroantimonate reactive cation.

Abstract

AbstractFor ultrastructural study of the formation and maturation of human eosinophil granules, bone marrow and buffy coat specimens were fixed with an aqueous solution of potassium pyroantimonate and osmium tetroxide and by conventional methods. The antimonate‐osmium tetroxide method of fixation, which is thought to permit ultrastructural localization of sodium or other cations, offered an advantage over routine methods in that it permitted recognition of four rather than two varieties of cytoplasmic granules in human eosinophils at various stages of cell development. These four granule varieties, designated A, B, C, and D, differed primarily in distribution and content of crystalloids and antimonate deposits: A granules lacked antimonate deposits and cystalloids; B granules contained a rim of deposits but lacked crystalloids; C granules possessed deposits that were present in the peripheral matrices but not in the central crystalloids; and D granules lacked deposits but contained crystalloids. Evidence is provided that these four varieties of granules represent progressive stages in the maturation of a single granule type and that granules without crystalloids are transformed into granules with crystalloids. The results also provide evidence for the presence of an as yet unidentified pyroantimonate precipitable cation in human eosinophil granules.