MODULATION OF HIV-1 REPLICATION BY CYTOKINES, SOLUBLE CY

巨噬细胞（MO）是体内第一个感染HIV-1的细胞，并作为病毒的储存库。细胞因子是HIV的有效调节剂，能够增强和抑制病毒复制。由于NK细胞是抵抗病毒感染细胞的第一道防线，并产生许多在MO上具有生物活性的细胞因子，因此我们研究了NK细胞产生能够阻止HIV在MO中复制的细胞因子的潜力。我们发现纯化的NK细胞和经过IL-2处理的NK细胞系是丰富的趋化因子来源，包括那些抑制HIV与趋化因子共受体（CCR3,CCR5）结合的细胞因子。我们还发现NK细胞产生高水平的IL-10和IL-13，这是一种具有强大的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，可以阻止病毒进入MO后的HIV-1复制，而T细胞则没有。部分纯化表明，抑制因子(s)是一个约10 kD的小分子，pI在8.0 ~ 10.0之间。小尺寸和基本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的能力，表明该因子不是通过与CCR-5结合而阻断的趋化因子。与此一致的是我们的发现，当感染后将NK细胞衍生因子添加到MO中时，β趋化因子的抗体，包括MIP-1a， MIP-1b和RANTES，无法逆转hiv -1抑制作用。相反，这些抗体逆转了在病毒吸附过程中加入该因子时产生的抑制作用。综上所述，我们的数据表明，新的NK细胞因子不同于已知的抑制HIV进入的β趋化因子，NK细胞可能在调节人类MO中HIV-1表达方面发挥比预期更大的作用。干扰素- α (IFN-a)在体外急性和慢性HIV-1感染系统中具有强大的抗逆转录病毒活性，其临床应用已在具有大量CD4+ T细胞的艾滋病患者中得到证实。然而，IFN-a在体外抑制HIV复制的能力各不相同，这可能与体内的不同作用有关。目前的研究将确定：1)IFN-a成分或重组杂交物种抑制急性HIV-1感染MO和T细胞的能力是否不同；2)抗hiv活性与诱导型一氧化氮合酶的表达有关；3)抗hiv活性与抗增殖活性相关；4)能否鉴定出一种低抗增殖活性、高抗hiv活性的IFN-a，使其在临床应用时毒副作用更小。

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 capable of 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 and NK cell lines treated with IL-2 are rich sources of chemokines, including those which inhibit binding to chemokine co-receptors (CCR3,CCR5)for HIV. 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 virus 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 blocking via binding to CCR-5. Consistent with this are our findings that antibodies to the beta chemokines, including MIP-1a, MIP-1b and RANTES, are unable to reverse the HIV-1-inhibitory effect when the NK cell-derived factor is added to MO post infection. In contrast, these antibodies reverse the inhibitory effects that occur when this factor is added during virus adsorption. 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. 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.