mature eosinophil mature eosinocyte polymorphonuclear leukocyte mature eosinophil leukocyte A fully differentiated eosinophil, a granular leukocyte with a nucleus that usually has two lobes connected by one or more slender threads, and cytoplasm containing coarse, round granules that are uniform in size and which can be stained by the dye eosin. Cells are also differentiated from other granulocytes by a small nuclear-to-cytoplasm ratio (1:3). This cell type is CD49d-positive. polymorphonuclear leucocyte Eosinophils are CD125-positive (IL-5R), GM-CSFR-positive, IL-3R-positive, VLA4-positive. They can also express MHC Class I & II, CD4, CD9, CD11a, CD11b, CD11c, CD13, CD15, CD16, CD17, CD18, CD24, CD25,CD28, CD29, CD32, CD33, CD35, CD37, CD39, CD43, CD44, CD45, CD45RB, CD45RO, CD46, CD47, CD48, CD49d, CD49f, CD50, CD52, CD53, CD54, CD55, CD58, CD59, CD62L, CD63, CD65, CD66, CD69, CD71, CD76, CD80, CD81, CD82, CD86, CD87, CD88, CD89, CD92, CD95, CD97, CD98, CD99, CD100, CD101, CD116, CD117, CD119, CD120, CD123, CD124, CD125, CD131, CD137, CD139, CD148, CD149, CD151, CD153, CD156, CD162, CD161, CD162, CD165, CD174, CD182, CD183, CD191, CD192, CD193, CD196, CD213, IL9R, ad integrin, beta-7 integrin, FceRI, IL13Ra1, TGFbR, PAFR, LTB4R, C3aR, CystLT1R, CystLT2R, fMLPR, CRTH2 (PGD2 receptor), histamine 4R, IDO, KYN, PAR-2, Siglec-8, Siglec-10, LIR1, LIR2, LIR3, LIR7, TLR7, TLR8, and VLA-4. Eosinophils can also secrete CXCL1, eotaxin-1, GM-CSF, IL-2, IL-3, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, IL-16, IL-18, IFN-gamma, LTC4, MIP-1alpha, NGF, PAF, RANTES, substance P, TGF-alpha, TGF-beta, TNF-alpha, and VIP. The status of eosinophils as true professional antigen presenting cells is unclear, despite their ability to present exogenous peptides and peptides processed from exogenous proteins (in certain studies) via MHC Class II and activate T cells. Per the equivalence axioms, 'eosinophil' is reasoned to be a subclass of 'professional antigen presenting cell', though the role of eosinophils as such in the body may be limited. mature eosinophil leucocyte eosinophil