Modulation of HIV Replication by Cytokines, Cytokine Ant

摘要：我们已经进行了一些研究，以确定细胞因子或它们的拮抗剂(抗细胞因子抗体或可溶性细胞因子受体)能够抑制HIV在人巨噬细胞(MO)或T细胞中的复制。在证明HIV感染的MO产生高水平的M-CSF和MIP-1a使HIV/MO储存库得以建立之后，我们发现M-CSF的拮抗剂在体外加入感染的MO时抑制HIV复制并减少MIP-1a的产生。这些M-CSF拮抗剂可能通过阻断MO产生病毒，减少HIV敏感细胞的趋化因子募集，以及防止体内HIV感染MO储存库的建立/维持而具有临床疗效(JI 2000)。淋巴因子IL-2用于恢复艾滋病患者的CD4+T细胞，据报道给药后可增加人单核细胞中的M-CSF，并引起血浆中HIV基因的一过性爆发。我们询问MO是否是HIV释放的来源，并发现在体外HIV感染之前MO暴露于IL-2会导致病毒复制急剧下降，这与IL-2诱导的CD4和CCR5表达下降有关。M-CSF的产生没有增加，这表明IL-2可能有助于预防MO感染，以及恢复T细胞功能(AIDS，1998)。 不同种类的干扰素在体外抑制HIV复制的能力不同，这可能与不同的治疗效果有关。我们发现，干扰素-α在抑制人类MO中HIV-1复制方面是有效的，但在与细胞趋向性(单核细胞与T细胞趋性)平行的T细胞中显示出相当大的变异。抗病毒和抗增殖活性之间没有相关性，也没有观察到MO和T细胞上CD4/CCR5/CXCR4表达的调节。未来的研究将确定不同种类的干扰素-a的抑制能力是否取决于趋化因子共受体，而不是感染艾滋病毒的细胞类型，以及这是否与干扰素-a疗法在艾滋病毒疾病中的毒性有关。 NK细胞是抵御病毒感染细胞的第一道防线，它产生的细胞因子对MO具有生物活性。我们发现，NK细胞产生了一种新的因子，可以防止病毒进入MO后复制HIV-1，但不能阻止T细胞。部分纯化表明，抑制因子(S)约为10kD，等电点为8-10，与趋化因子相似。这种因子能够抑制HIV的复制，而不是病毒的进入，并且针对β趋化因子的抗体无法逆转这种抑制，这表明这种NK细胞因子是独特的，可能在调节人类MO中HIV-1的表达方面发挥作用。 最近的研究集中在识别不同于CD4、CCR5和CXCR4的分子，这些分子参与了HIV的进入。我们的目的是确定针对这些结构的药物，并防止艾滋病毒包膜与细胞膜融合和/或病毒衣壳进入细胞质。 我们还将确定这些抑制剂是否可以由于调节细胞信号和/或细胞因子产生而产生威慑作用。

Summary: We have conducted studies to identify cytokines or their antagonists (anti-cytokine antibodies or soluble cytokine receptors) capable of inhibiting HIV replication in human macrophages (MO) or T cells. Subsequent to showing that HIV-infected MO produce high levels of M-CSF and MIP-1a, which enable an HIV/MO reservoir to be established, we found that antagonists to M-CSF inhibit HIV replication and reduce production of MIP-1a when added to infected MO in vitro. These M-CSF antagonists may have clinical benefit as therapies for HIV by blocking production of virus by MO, reducing chemokine recruitment of HIV susceptible cells, and preventing establishment/maintenance of HIV-infected MO reservoirs in vivo (JI 2000). The lymphokine IL-2, used for restoration of CD4+ T cells in AIDS patients, was reported to increase M-CSF in human monocytes and cause a transient burst of HIV mRNA in plasma after administration. We asked if MO were the source of released HIV and found that exposure of MO to IL-2 prior to HIV infection in vitro leads to a dramatic decrease in virus replication, which correlates with an IL-2-induced decrease of CD4 and CCR5 expression. Production of M-CSF was not enhanced, suggesting that IL-2 may be beneficial in preventing MO infection, as well as restoring T cell function (AIDS 1998). Interferon-alpha (IFN-a) species differ in their ability to inhibit HIV replication in vitro, which may correlate with the varying therapeutic effects. We found that IFN-a species are effective at inhibiting HIV-1 replication in human MO, but show considerable variation in T cells that parallels cellular tropism (monocyte vs. T cell tropic). No correlation existed between antiviral and antiproliferative activity; modulation of CD4/CCR5/CXCR4 expression on MO and T cells was also not observed. Future studies will determine whether the inhibitory capacity of various species of IFN-a depends on the chemokine co-receptor, rather than the cell type infected with HIV, and whether this contributes to the toxicities associated with IFN-a therapy in HIV disease. NK cells are the first line of defense against virus-infected cells and produce cytokines that are biologically active on MO. We found that NK cells produce a novel factor which prevents HIV-1 replication following virus entry in MO, but not T cells. Partial purification indicates that the inhibitory factor(s) is approximately 10 kD with a pI of 8-10, similar to chemokines. The ability of this factor to inhibit replication of HIV, and not virus entry, and the failure of antibodies to beta chemokines to reverse the inhibition suggest that this NK cell factor is unique and may play a role in the regulation of HIV-1 expression in human MO. More recent studies focus on the identification of molecules distinct from CD4, CCR5 and CXCR4, that are involved in HIV entry. Our intent is to identify agents that target these structures and prevent fusion of the HIV envelope with the cell membrane and/or delivery of the viral capsid into the cytoplasm. We will also determine whether such inhibitors can cause deterimental effects due to modulation of cell signalling and/or cytokine production.