MODULATION OF HIV-1 REPLICATION BY CYTOKINES AND SOLUBLE CYTOKINE RECEPTORS

巨噬细胞（MO）是体内感染HIV-1的第一批细胞，并作为病毒的储存库。细胞因子是HIV的有效调节剂，既增强又抑制病毒复制。由于NK细胞是抵抗病毒感染细胞的第一道防线，并产生许多对MO具有生物活性的细胞因子，因此我们研究了NK细胞产生能够防止MO中HIV复制的细胞因子的潜力。我们发现用IL-2处理的纯化的NK细胞和NK细胞系NK3.3和YT是趋化因子的丰富来源，包括抑制与HIV的CCR-3和CCR-5趋化因子共受体结合的趋化因子和具有单核细胞和T细胞趋化/活化特性的趋化因子。因此，NK细胞产生能够通过多种趋化因子受体进行信号传导的多种趋化因子。我们还发现NK细胞产生高水平的IL-10以及IL-13，这是一种具有强效单核细胞分化特性和HIV抑制活性的细胞因子，但不产生IL-4。最后，我们发现NK细胞产生一种新的因子，它阻止HIV-1进入MO后复制，而不是T细胞。部分纯化表明抑制因子是一种约10 kD的小分子，pI在8.0和10.0之间。小尺寸和碱性pI是趋化因子的特征，但该因子抑制HIV复制的能力，而不仅仅是病毒进入，表明该因子不是与CCR-5结合的趋化因子。与此一致的是，我们的发现是，当感染后将NK细胞衍生因子加入MO时，β趋化因子（包括MIP-1 α、MIP-1 β和RANTES）的抗体不能逆转HIV-1抑制作用。相反，这些抗体可以逆转在病毒吸附过程中加入该因子时观察到的抑制作用。百日咳毒素是G蛋白偶联受体活性的有效抑制剂，对抑制活性没有影响。两者合计，我们的数据表明，新的NK细胞因子是不同的β趋化因子已知抑制HIV进入和NK细胞可能发挥更大的作用比预期的调节HIV-1在人类MO的表达。重要的是要确定参与的细胞因子，并描绘其在体外和体内抑制HIV复制的潜力。 干扰素-α（IFN-α）在体外急性和慢性HIV-1感染系统中具有有效的抗逆转录病毒活性，并且其临床效用已在具有高数量的CD 4 + T细胞的AIDS患者中显示。然而，IFN-a种类在体外抑制HIV复制的能力上不同，这可能与体内不同的作用相关。目前的研究将确定：1）IFN-α组分或重组杂合物种是否在它们抑制MO和T细胞的急性HIV-1感染的能力方面不同; 2）抗HIV活性与诱导型一氧化氮合酶的表达相关; 3）抗HIV活性与抗增殖活性相关;以及4）是否可以鉴定出具有低抗增殖活性和高抗HIV活性的IFN-α种类，其在临床上使用时可能引起较少的毒副作用。

Macrophages (MO) are the first cells infected with HIV-1 in vivo and act as a reservoir for the virus. Cytokines are potent modulators of HIV, both enhancing and inhibiting virus replication. Since NK cells are the first line of defense against virus-infected cells and produce a number of cytokines which are biologically active on MO, we investigated the potential of NK cells to produce cytokines capable of preventing replication of HIV in MO. We found that purified NK cells treated with IL-2 and the NK cell lines, NK3.3 and YT, are rich sources of chemokines, including those which inhibit binding to the CCR-3 and CCR-5 chemokine co-receptors for HIV and those with monocyte and T cell chemotactic/ activating properties. Thus, NK cells produce multiple chemotactic factors capable of signalling through a wide variety of chemokine receptors. We also found that NK cells produce high levels of IL-10 as well as IL-13, a cytokine with potent monocyte differentiating properties and HIV inhibitory activity, but do not produce IL-4. Finally, we found that NK cells produce a novel factor which prevents HIV-1 replication following entry in MO, but not T cells. Partial purification indicates that the inhibitory factor(s) is a small molecule of approximately 10 kD with a pI between 8.0 and 10.0. The small size and basic pI are characteristic of a chemokine, but the ability of this factor to inhibit replication of HIV, and not merely virus entry, indicate that the factor is not a chemokine binding to CCR-5. Consistent with this are our findings that antibodies to the beta chemokines, including MIP-1 alpha, MIP-1 beta and RANTES, are unable to reverse the HIV-1-inhibitory effect when the NK cell-derived factor is added post infection to MO. In contrast, these antibodies can reverse the inhibitory effects observed when this factor is added during virus adsorption. Pertusis toxin, a potent inhibitor of G-protein coupled receptor activity, had no effect on the inhibitory activity. Taken together, our data suggest that the novel NK cell factor is distinct from beta chemokines known to inhibit HIV entry and that NK cells may play a greater role than anticipated in the regulation of HIV-1 expression in human MO. It is important to identify the cytokines involved and delineate their potential to inhibit HIV replication in vitro and in vivo. Interferon-alpha (IFN-a) has potent anti-retroviral activity in acute and chronic HIV-1 infection systems in vitro and its clinical utility has been shown in AIDS patients having high numbers of CD4+ T cells. However, IFN-a species vary in their ability to inhibit HIV replication in vitro, which may correlate with varying effects in vivo. Current studies will determine whether: 1) IFN-a components or recombinant hybrid species vary in their ability to inhibit acute HIV-1 infections of MO and T cells; 2) anti-HIV activity is associated with expression of inducible nitric oxide synthase; 3) anti-HIV activity correlates with anti-proliferative activity; and 4) whether a species of IFN-a with low anti-proliferative activity and high anti-HIV activity can be identified, which may cause fewer toxic side effects when used clinically.