Eosinophils function as antigen-presenting cells.
Eosinophils release lipid mediators, including leukotriene C4, platelet-activating factor, and liposins, and contain four distinct granule cationic proteins, major basic protein, eosinophil peroxidase, eosinophil cationic protein, and eosinophil-derived neurotoxin, which may cause dysfunction and destruction of other cells. Eosinophils are primarily thought of as terminal effectors of allergic responses and of parasite elimination. Eosinophils are characteristically present within the airway lumina of asthmatics, and these airway eosinophils have been induced in vivo to express major histocompatibility complex II (MHC-II) complexes and costimulatory molecules, which are required for T lymphocytes to be functionally activated. In in vitro experiments, eosinophils can process antigen and express the costimulatory molecules, and after cytokine-elicited induction of MHC-II, expression can function as antigen-presenting cells in stimulating T lymphocyte responses. Airway luminal eosinophils can migrate into draining paratracheal lymph nodes, localized to T cell-rich paracortical areas, and stimulate antigen-specific T cell proliferation in vivo within paratracheal lymph nodes, which was CD80- and CD86-dependent and limited to CD4+ T cells. Furthermore, eosinophils within the lumina of airways promote expansion of T helper cell type 2 (Th2) by presenting antigen, suggesting that eosinophils actively modulate immune responses by amplifying Th2 cell responses.
Shi
Huan-Zhong
HZ
First Affiliated Hospital, Guangxi Medical University, Nanning 530021, Guangxi, P. R. China. hzshi@tom.com
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D001249:Asthma / Q000276:immunology / Q000503:physiopathology; D002454:Cell Differentiation / Q000276:immunology; D004804:Eosinophils / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D020545:Respiratory Mucosa / Q000276:immunology* / Q000503:physiopathology; D018418:Th2 Cells / Q000166:cytology / Q000276:immunology
D000949:Histocompatibility Antigens Class II