11月版的American Journal of Pathology雜志上發(fā)表了澳大利亞Alberta大學(xué)研究人員有關(guān)嗜酸性粒細(xì)胞(eosinophil)在免疫發(fā)育過程中重要作用的研究論文。
當(dāng)免疫系統(tǒng)對環(huán)境中無害的物質(zhì)如花粉或霉菌產(chǎn)生不正常應(yīng)答時，常常導(dǎo)致哮喘或過敏性疾病發(fā)生,。常見的過敏性疾病有,，濕疹，蕁麻疹,，花粉熱,，哮喘，食物過敏等,。
根據(jù)接受刺激后產(chǎn)生炎癥的類型和分泌物,，可以將免疫應(yīng)答分為Th1型和Th2型。Th1免疫應(yīng)答一般針對細(xì)胞內(nèi)感染,，如細(xì)菌或病毒感染,。而Th2免疫應(yīng)答則針對較大的寄生蟲，如線蟲感染,。而哮喘和過敏性疾病通常是由于產(chǎn)生了不正常的Th2免疫應(yīng)答,。
雖然嗜酸性粒細(xì)胞作為一種免疫細(xì)胞，一直被認(rèn)為可以調(diào)節(jié)過敏反應(yīng)以及哮喘Th2免疫應(yīng)答，同時也可能是控制Th1 和Th2免疫應(yīng)答的重要開關(guān),。因此,，研究人員對兒童胸腺中嗜酸性粒細(xì)胞發(fā)育進行研究。胸腺是人體的免疫器官,，也是早期Th1/Th2分化的場所,，隨著年齡的增長會逐漸萎縮。研究表明,，胸腺IDO+嗜酸性粒細(xì)胞(Thymic Indoleamine 2,3-Dioxygenase Positive Eosinophils)在人類嬰兒期或許對Th2免疫應(yīng)答具有免疫調(diào)節(jié)作用,。（生物谷Bioon.com）
生物谷推薦原始出處：
American Journal of Pathology. 2009;175:2043-2052. DOI: 10.2353/ajpath.2009.090015
Thymic Indoleamine 2,3-Dioxygenase-Positive Eosinophils in Young Children
Potential Role In Maturation of the Naive Immune System
Meri K. Tulic*, Peter D. Sly, David Andrews, Maxine Crook, Francis Davoine?, Solomon O. Odemuyiwa?, Adrian Charles, Megan L. Hodder*, Susan L. Prescott*, Patrick G. Holt and Redwan Moqbel
From the School of Paediatric and Child Health,* and the Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth, Australia; the Divisions of Cardiac Surgery and Paediatric Pathology, PathWest Laboratory Medicine, Princess Margaret Hospital, Perth, Australia; and the Pulmonary Research Group,? University of Alberta, Edmonton, Canada
Eosinophils expressing indoleamine 2, 3-dioxygenase (IDO) may contribute to T-helper cell (Th)2 predominance. To characterize human thymus IDO+ eosinophil ontogeny relative to Th2 regulatory gene expression, we processed surgically obtained thymi from 22 children (age: 7 days to 12 years) for immunohistochemistry and molecular analysis, and measured cytokine and kynurenine levels in tissue homogenates. Luna+ eosinophils (2% of total thymic cells) decreased in number with age (P = 0.02) and were IDO+. Thymic IDO immunoreactivity (P = 0.01) and kynurenine concentration (P = 0.01) decreased with age as well. In addition, constitutively-expressed interleukin (IL)-5 and IL-13 in thymus supernatants was highest in youngest children. Eosinophil numbers correlated positively with expression of the Th2 cytokines IL-5, IL-13 (r = 0.44, P = 0.002), and IL-4 (r = 0.46, P = 0.005), transcription factor signal transducer and activator of transcription-6 (r = 0.68, P = 0.001), and the chemokine receptor, CCR3 (r = 0.17, P = 0.04), but negatively with IL-17 mRNA (r = –0.57, P = 0.02) and toll-like receptor 4 expression (r = –0.74, P = 0.002). Taken together, these results suggest that functional thymic IDO+ eosinophils during human infant life may have an immunomodulatory role in Th2 immune responses.
