PATHOGENIC EFFECTS OF HUMAN RETROVIRUSES ON HEMATOPOIETIC AND ADHERENT CELLS

这个项目的目标是更好地了解主机的影响 细胞和其他辅助因子对人逆转录病毒复制的影响， 发病机制 在开发了感染性分子克隆之后， 人类T细胞白血病/淋巴瘤病毒I型（HTLV-I），我们确定 无细胞感染导致细胞因子依赖性转化 并且HTLV-1的p12和p30开放阅读框架不需要 转型 现在很清楚，HTLV，HIV和人类泡沫病毒， 在生产性感染和潜伏性感染之间存在平衡。 在艾滋病患者中，我们和其他人发现，这种平衡可以 受到免疫刺激和甲基化的影响我们正在研究 使用T细胞改变这种平衡的致病性后果， 单核细胞/巨噬细胞。来自无症状HIV+个体的单核细胞 含有潜伏的艾滋病毒 这些单核细胞与Con 来自HIV阴性正常供体的A活化T细胞，这些单核细胞 表达的病毒。 在潜伏感染的THP-1中，产生了传染性病毒 在5-氮杂胞苷暴露后。因为这表明细胞 甲基化在HIV复制中起作用，我们研究了HIV 感染可导致细胞基因的异常甲基化。 一 IFN-γ的从头甲基化显著增加， 启动子，这与表达下降，在这些 急性感染细胞 一种CD 4+淋巴细胞系-JMO，其表达 IFN-γ组成型，使用表达载体稳定转染， 含有反义方向（TMH）的DNA MTase cDNA的载体。 RNA酶保护分析表明， 表达反义MTase的JMO中的MTase表达。南部 分析显示JMO中IFN-γ启动子的半甲基化 表达亲本neo构建体的细胞系，而JMO-TMH是 完全低甲基化细胞系中IFN-γ的产生 组成型产生MTase反义核酸JMO-TMH， 高于组成型表达亲本载体的细胞系。 在急性感染HIV后，HIV-1的表达大大降低， JMO-TMH可能是由于高水平的IFN-γ。 由于IFN-γ 在宿主防御病毒感染中起主要作用， 启动子的高甲基化，导致IFN γ减少 产生是HIV-1逃避免疫应答的一种机制。

The goal of this project is to better understand the effects of host cells and other co-factors on human retroviral replication and pathogenesis. After development of the infectious molecular clone of Human T cell Leukemia/Lymphoma virus type I (HTLV-I), we determined that cell-free infection results in cytokine dependent transformation and that p12 and p30 open reading frames of HTLV-I are not needed for transformation. It is now clear that HTLV, HIV and Human Foamy Virus, there is a balance between productive infection and latent infection. In AIDS patients, we and others has found that this equilibrium can upset by immune stimulation and methylation. We are studying the pathogenic consequences of altering this balance using T cells and monocyte/ macrophages. Monocytes from asymptomatic HIV+ individuals contained latent HIV. After coculture of these monocytes with Con A-activated T-cells from HIV negative normal donors, these monocytes expressed virus. In latently infected THP-1, infectious virus was made after 5-azacytidine exposure. Since this suggests that cellular methylation plays a role in HIV replication, we studied whether HIV infection could result in aberrant methylation of cellular genes. A significant increase in the de novo methylation of the IFN-gamma promoter, which correlated with decreased expression, was seen in these acutely infected cells. A CD4+ lymphoid cell line-JMO, which expresses IFN-gamma constitutively, was stablely transfected using expression vectors containing DNA MTase cDNA in the antisense orientation (TMH). RNase protection analyses demonstrated a significantly lower level of MTase expression in the JMO expressing antisense MTase. Southern analysis showed hemimethylation of the IFN-gamma promoter in the JMO cell line expressing the parental neo construct while JMO-TMH was completely hypomethylated. IFN-gamma production in cell line constitutively producing MTase antisense, JMO-TMH, was significantly higher than a cell line constitutively expressing the parental vector. After acute infection of HIV, HIV-1 expression was greatly reduced in JMO-TMH presumably due to the high level of IFN-gamma. Since IFN-gamma plays a major role in host defense against viral infection, hypermethylation of the promoter which results in decreased IFNgamma production is one mechanism by which HIV-1 evades the immune response.