The Enigma of Eosinophil Degranulation

Abstract

Eosinophils are specialized white blood cells, which are involved in the pathology of diverse allergic and nonallergic inflammatory diseases. Eosinophils are traditionally known as cytotoxic effector cells but have been suggested to additionally play a role in immunomodulation and maintenance of homeostasis. The exact role of these granule-containing leukocytes in health and diseases is still a matter of debate. Degranulation is one of the key effector functions of eosinophils in response to diverse stimuli. The different degranulation patterns occurring in eosinophils (piecemeal degranulation, exocytosis and cytolysis) have been extensively studied in the last few years. However, the exact mechanism of the diverse degranulation types remains unknown and is still under investigation. In this review, we focus on recent findings and highlight the diversity of stimulation and methods used to evaluate eosinophil degranulation.

Eosinophils Decrease Pulmonary Metastatic Mammary Tumor Growth

“…While we found no detectable TNFα and IFNγ in co-culture supernatants (below level of detection, data not shown), there was a small increase in Granzyme B in co-cultures containing both eosinophils and EO771-GFP cells compared to eosinophils cultured alone ( Figure 2E ). Since Granzyme B can be a component of eosinophil granules ( 23 , 29 ), these data suggest eosinophils co-cultured with EO771-GFP tumor cells may be degranulating. To generate an additional measure of eosinophil degranulation, we collected supernatants from eosinophil-tumor cell co-cultures at 1:10, 1:20, and 1:40 T:E ratios and assessed peroxidase activity via the OPD method.…”

Methodological Approaches To Assess Innate Immunity and Innate Memory in Marine Invertebrates and Humans

“…The release of neutrophil extracellular traps (NETs) upon toxicant-induced neutrophil activation or death can be evaluated by a live cell imaging method (Keshavan et al, 2019). Degranulation of basophils and eosinophils is also used for assessing the toxicity of various agents, and is generally measured using cell lines or blood cells from patients with eosinophilia or basophilia and assessing the stimulus-induced in vitro release of pre-formed mediators (e.g., histamine, Major Basic Protein) (Masilamani et al, 2017;Fettrelet et al, 2021).…”

“…Degranulation of basophils and eosinophils is also used for assessing the toxicity of various agents, and is generally measured using cell lines or blood cells from patients with eosinophilia or basophilia and assessing the stimulus-induced in vitro release of pre-formed mediators ( e.g. , histamine, Major Basic Protein) ( Masilamani et al, 2017 ; Fettrelet et al, 2021 ).…”

La neurotoxine dérivée des éosinophiles (EDN) : intérêt du dosage dans les pathologies mastocytaires

“…Les PNE peuvent libérer leur contenu sécrétoire par trois mécanismes (38,49,50) : Le rôle principal en physiologie de l'ECP est un rôle cytotoxique en contribuant à la création de pores transmembranaires dans les cellules cibles, le plus souvent des parasites. (55).…”