Human eosinophil (EOS)

Human eosinophils are specialized granulocytic white blood cells that serve as key effectors in the innate immune system, primarily recognized for their role in defending against helminthic parasites and their involvement in the pathogenesis of allergic diseases [NIH, 2023]. They develop in the bone marrow from myeloid progenitors under the influence of cytokines such as IL-3, GM-CSF, and most critically, IL-5, which governs their production, activation, and survival [PubMed: PMC3916387]. Once recruited to tissues, eosinophils release highly basic cytotoxic proteins and lipid mediators that can cause significant collateral damage to host tissues, contributing to the chronic airway remodeling seen in severe asthma and the organ dysfunction characteristic of hypereosinophilic syndromes [StatPearls, 2023]. In the context of drug development, eosinophils are considered a 'target' for depletion or functional inhibition, particularly through monoclonal antibodies that block the IL-5 pathway or target surface receptors like Siglec-8 to induce apoptosis. While effective in reducing exacerbations in eosinophilic diseases, the systemic depletion of these cells requires monitoring for impaired host defense against certain infections.

Other names

Eosinophilic granulocyteAcidophilEosinophil leukocyte

Therapeutic strategies targeting eosinophils include the neutralization of interleukin-5 (IL-5) to inhibit cell maturation and survival (e.g., Mepolizumab), the use of afucosylated antibodies to induce antibody-dependent cellular cytotoxicity (ADCC) via NK cells for direct depletion (e.g., Benralizumab), and the induction of eosinophil apoptosis through glucocorticoid receptor activation (e.g., Dexamethasone) [StatPearls, 2023; PubMed: PMC3916387].