Cytokine receptor-mediated trafficking of preformed IL-4 in eosinophils identifies an innate immune mechanism of cytokine secretion

Mechanisms of eosinophil secretion: large vesiculotubular carriers mediate transport and release of granule-derived cytokines and other proteins

“…EoSVs, in conjunction with small, classical, round vesicles, represent alternative pathways for transport of granule products to the plasma membrane for extracellular release [44,45]. Both vesicular compartments are immunolabeled positively for typical granule products [43,44].…”

“…Recent data have brought conclusive evidence for the participation of morphologically distinct, large, membrane-bound, tubular compartments in the eosinophil secretory route [43][44][45]. Although these vesiculotubular structures have long been recognized in the cytoplasm of eosinophils [48][49][50] (Fig.…”

“…How these transport vesicles are formed and mediate the rapid and specific secretion of eosinophil proteins are questions, which have been addressed recently. In addition to small, classical, round vesicles, it has now become apparent that the eosinophil secretory pathway is mediated by morphologically distinct, large pleiomorphic vesiculotubular carriers, termed eosinophil sombrero vesicles (EoSVs), which are responsible for moving proteins between granules and the plasma membrane [43][44][45]. During eosinophil secretion, EoSVs are actively formed from granules and direct differential release of proteins.…”

Factors Driving the Aspirin Exacerbated Respiratory Disease Phenotype

“…[53][54][55] Eosinophils secrete numerous cytokines and chemokines, 54 and unlike lymphocytes, eosinophils store these cytokines preformed within granules that can be instantly released with activation. 55,56 The robust expression of interleukin (IL)-4 in AERD did not extent to IL-5 ( Fig. 2), likely representing the physiology of eosinophils, specifically that IL-4 but not IL-5 is a prominent eosinophil-derived cytokine.…”

Reply to Eosinophil cytolysis and release of cell-free granules

“…A second type of degranulation, piecemeal degranulation, is a process that was first defined by the electron microscopic observations of Dvorak and colleagues 3 , who noted that, similarly to what had been observed for basophils, eosinophil granules do not empty as completely or as explosively as would be anticipated if exocytosis were taking place 4 . As discussed in detail in the original Review 1 , recent studies by Spencer, Melo, Weller and colleagues 5,6 have identified tubulovesicular subcellular structures and have elucidated receptorchaperone systems that are the among the important features underlying piecemeal degranulation.…”