【摘要】：人免疫缺陷病毒(human immunodeficiency virus, HIV)感染的特征是外周血、淋巴器官以及黏膜組織中的CD4+T細(xì)胞數(shù)量的漸進(jìn)性耗竭。雖然HIV-1感染CD4+T細(xì)胞及其他的免疫細(xì)胞是病程發(fā)展的主要驅(qū)動力,但艾滋病以及疾病的轉(zhuǎn)歸不僅是病毒的致細(xì)胞病變效應(yīng)所致,更是由于復(fù)雜的病毒-宿主間相互作用而最終導(dǎo)致,如免疫系統(tǒng)持續(xù)性活化以及T細(xì)胞穩(wěn)態(tài)的失衡。其中,持續(xù)性免疫活化被認(rèn)為是除了病毒復(fù)制水平之外決定疾病進(jìn)展的重要因素。引起HIV-1相關(guān)免疫活化的因素很多,其中微生物產(chǎn)物從受損胃腸道黏膜轉(zhuǎn)移到系統(tǒng)循環(huán)中是一個重要因素。雖然有效的抗逆轉(zhuǎn)錄病毒治療(antiretroviral therapy, ART)能夠較好地抑制HIV-1復(fù)制,但并不能降低免疫活化至正常水平。因此探究HIV-1感染中固有免疫系統(tǒng)的調(diào)控機(jī)制對于控制免疫活化及免疫干預(yù)治療策略具有重要意義。 慢性感染中由于病原體相關(guān)分子模式(pathogen-associated molecular patterns, PAMP)對固有免疫細(xì)胞的長期刺激,導(dǎo)致持續(xù)的免疫活化,I型干擾素(type I interferon, IFN-I)大量產(chǎn)生,引起干擾素誘導(dǎo)基因(interferon-stimulated genes, ISGs)的表達(dá)上調(diào)。盡管大多數(shù)ISGs起到控制病毒復(fù)制的重要作用,但其中一些可能發(fā)揮補(bǔ)償性的免疫抑制效應(yīng)以限制病理性的功能失調(diào)進(jìn)一步惡化。 本研究通過轉(zhuǎn)錄組芯片數(shù)據(jù)分析,發(fā)現(xiàn)淋巴細(xì)胞抗原6復(fù)合體E(lymphocyte antigen6complex, locus E, LY6E)在HIV-1進(jìn)展者血液標(biāo)本中的表達(dá)顯著高于不進(jìn)展者,并且能被IFN-a誘導(dǎo)表達(dá)上調(diào)。進(jìn)一步檢測感染者的單核細(xì)胞中LY6E的表達(dá)水平,發(fā)現(xiàn)其與CD4+T細(xì)胞數(shù)量降低、CD8+T細(xì)胞的免疫活化程度均密切相關(guān),縱向隨訪表明LY6E表達(dá)高的病人病程進(jìn)展更快。 為了進(jìn)一步研究LY6E在單核細(xì)胞介導(dǎo)的固有免疫應(yīng)答中的作用,通過短發(fā)夾RNA (short hairpin RNA, shRNA)或小干擾RNA (small interfering RNA,siRNA)技術(shù)沉默了單核細(xì)胞中的LY6E,結(jié)果表明單核細(xì)胞中的LY6E可負(fù)向調(diào)控CD14的表達(dá),并導(dǎo)致LPS刺激引起的固有免疫應(yīng)答減弱。 HIV-1慢性感染中,單核細(xì)胞中的LY6E上調(diào)水平與CD14的下調(diào)水平密切相關(guān)。體外實驗表明,未治療的感染者中LPS引起的單核細(xì)胞免疫應(yīng)答要高于健康組和ART治療組。而LY6E依然能夠下調(diào)感染者單核細(xì)胞的CD14表達(dá)以及減弱LPS誘導(dǎo)的免疫應(yīng)答水平。LY6E的免疫抑制效應(yīng)在慢性感染期起到對過度免疫活化的代償性平衡作用,雖然其抑制能力不足以使活化的單核細(xì)胞的高應(yīng)答能力得以恢復(fù)到正常水平,但在一定程度上可以避免因過度活化造成宿主的病理損傷。 綜上所述,本文發(fā)現(xiàn)了LY6E作為一個免疫調(diào)節(jié)基因,在HIV-1慢性感染中對LPS所致的固有免疫活化起到調(diào)控作用,是平衡單核細(xì)胞活化的一種負(fù)反饋機(jī)制,可作為免疫干預(yù)策略的一個新靶標(biāo)。
[Abstract]:Human immunodeficiency virus (human immunodeficiency virus, HIV) infection is characterized by progressive depletion of CD4 T cells in peripheral blood, lymphoid organs and mucous membranes. Although HIV-1 infection with CD4 T cells and other immune cells is the main driving force of the course of disease, AIDS and the prognosis of the disease are not only caused by the cytopathic effect of the virus. It is also due to the complex virus-host interaction, such as the persistent activation of the immune system and the imbalance of T cell homeostasis. Among them, persistent immune activation is considered to be an important factor in determining disease progress in addition to virus replication level. There are many factors causing HIV-1 related immune activation, among which the transfer of microbial products from damaged gastrointestinal mucosa to systemic circulation is an important factor. Although effective antiretrovirus treatment of (antiretroviral therapy, ART) can inhibit HIV-1 replication, it can not reduce immune activation to normal level. Therefore, it is of great significance to explore the regulation mechanism of innate immune system in HIV-1 infection in order to control immune activation and immune intervention therapy strategy. In chronic infection, interferon I (type I interferon, IFN-I is produced in large numbers due to the long-term stimulation of innate immune cells by pathogen-associated molecular patterns, PAMP), which leads to continuous immune activation. The expression of interferon induced gene (interferon-stimulated genes, ISGs) was up-regulated. Although most ISGs play an important role in controlling viral replication, some of them may play a complementary immunosuppressive effect to limit the further deterioration of pathological dysfunction. In this study, through the analysis of microarray data of transcriptional group, it was found that the expression of E (lymphocyte antigen6complex, locus E, LY6E) in blood samples of HIV-1 progressive patients was significantly higher than that of non-progressive HIV-1 patients, and could be up-regulated by IFN-a. The expression of LY6E in monocytes of infected patients was further detected, and it was found that it was closely related to the decrease of the number of CD4 T cells and the degree of immune activation of CD8 T cells. Longitudinal follow-up showed that the patients with high expression of LY6E advanced faster in the course of disease. In order to further study the role of LY6E in monocyte-mediated innate immune response, LY6E, in monocytes was silenced by short hairpin RNA (short hairpin RNA, shRNA) or small interfering RNA (small interfering RNA,siRNA) technique. The results showed that LY6E in monocytes could negatively regulate the expression of CD14 and weaken the innate immune response induced by LPS stimulation. In chronic HIV-1 infection, the up-regulation of LY6E in monocytes is closely related to the down-regulation of CD14. In vitro experiments showed that the monocyte immune response induced by LPS in untreated infected patients was higher than that in healthy group and ART treatment group. However, LY6E can still down-regulate the expression of CD14 in monocytes and weaken the level of immune response induced by LPS. The immunosuppressive effect of Ly6E plays a compensative role in the stage of chronic infection. Although its inhibitory ability is not enough to restore the high response ability of activated monocytes to the normal level, to a certain extent, it can avoid the pathological damage of the host caused by excessive activation. In conclusion, we found that LY6E, as an immunomodulatory gene, plays a regulatory role in the intrinsic immune activation induced by LPS in HIV-1 chronic infection, and is a negative feedback mechanism to balance monocyte activation. It can be used as a new target of immune intervention strategy.
【學(xué)位授予單位】：南開大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：R512.91

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 ;Regulation of Toll-like receptor signaling in innate immunity[J];Science China(Life Sciences);2010年01期

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本文編號：2482248