Functional and biochemical relationships between tropism, infectivity, and neut

趋化因子受体作为HIV进入的辅助受体的鉴定，不仅有助于理解病毒的嗜性，而且为HIV疾病的治疗干预提供了另一个靶点。 几种趋化因子受体已被证明作为HIV-1进入的辅助受体。 主要的是CXCR 4（针对T细胞系嗜性病毒）和CCR 5（针对巨噬细胞嗜性病毒）。 由于艾滋病毒在选择性压力下的适应能力，任何旨在阻断艾滋病毒与一种辅助受体相互作用的药物都可能迫使病毒使用其他辅助受体。 因此，确定完整的辅助受体库是必要的。由于STRL 33在所有淋巴组织中表达，我们与NIAID的J. Farber博士合作，测试了它与HIV的共受体活性。STRL 33在Jurkat细胞中的表达增加了对HIV-1的ELI 1分离株感染的耐受性。 因此，STRL 33在体外可作为HIV-1辅助受体。 除了测试STRL 33与许多不同表型的HIV-1毒株的共受体活性外，我们还开始了对HIV-2和SIV的研究。 我们已经在感染性试验中表明，HIV-1的MAL株和SIV的mac 239分离株使用STRL 33，但不如它们使用CCR 5。 在培养物中仅在约30天后出现病毒指示适应。 为了证实这一点，使用约35天后出现的病毒感染新鲜Jurkat-STRL 33细胞以及亲本Jurkat细胞。 在第二次传代中，在约12天后观察到病毒产生，从而证明SIVmac 239和HIV-1 MAL均已适应更有效地使用STRL 33。重要的是，这些传代病毒仍然不能感染Jurkat细胞。 传代的病毒已经适应使用STRL 33，这由针对STRL 33产生的抗体抑制病毒感染的事实证明。 我们已经从适应的MAL病毒中克隆了12个包膜基因，从适应的SIVmac 239中克隆了6个env基因。 我们目前正在将这些基因返回感染性分子克隆，以评估其生物活性。 基于SIV和HIV-1等多种病毒的细胞嗜性，我们预测在SUP-T1细胞上存在另一种辅助受体。 我们已经克隆了这种辅助受体，并将其鉴定为CCR 9，一种TECK（CCL 25）的趋化因子受体。 CCR 9以两种形式存在，A和B，在N末端相差12个氨基酸。 CCR 9 B对包括SIVagmSAB和SIVagmTAN在内的几种SIV毒株具有活性，但迄今为止还没有发现使用该分子作为进入辅因子的HIV-1。正在筛选其他HIV-1分离株，包括主要分离株。由于CCR 9 A/B在胸腺细胞和运输到肠道的淋巴细胞亚群中表达，并且由于这些组织对HIV疾病和AIDS发病机制的明显重要性，我们正在扩大我们的研究，包括在这些细胞中表达的辅助受体以及这些细胞和树突状细胞的感染，树突状细胞分泌CCL 25，因此可以募集T细胞。

The identification of chemokine receptors as coreceptors for HIV entry, not only has contributed to the understanding on viral tropism but has provided an additional target for therapeutic intervention for HIV disease. Several chemokine receptors have been shown to function as coreceptors for HIV-1 entry. The main ones are CXCR4 (for T-cell line tropic viruses) and CCR5 (for macrophage-tropic viruses). Because of the capacity of HIV to adapt when selective pressures are imposed, it is likely that any drug designed to block the interaction of HIV with one coreceptor will force the virus to use additional coreceptors. Thus, the determination of the complete coreceptor repertoire is necessary. Because STRL33 is expressed in all lymphoid tissues, in collaboration with Dr J. Farber, NIAID, we tested it for coreceptor activity with HIV. STRL33 expression in Jurkat cells conferred increased permissivity to infection by the ELI1 isolate of HIV-1. Thus, STRL33 can act as an HIV-1 coreceptor in vitro. As well as testing the coreceptor activity of STRL33 with a number of HIV-1 strains of different phenotypes, we have begun studies with HIV-2 and SIV. We have shown, in an infectivity assay, that the MAL strain of HIV-1 and the mac239 isolate of SIV use STRL33 but not as well as they use CCR5. The appearance of virus only after about 30 days in culture is indicative of adaptation. To confirm this, virus emerging after about 35 days was used to infect fresh Jurkat- STRL33 cells as well as the parent Jurkat cells. In this second passage, virus production was seen after about 12 days, thus demonstrating that both SIVmac239 and HIV-1 MAL had adapted to use STRL33 more efficiently. Importantly, these passaged viruses were still unable to infect Jurkat cells. That the passaged virus had adapted to use STRL33 was demonstrated by the fact that an antibody raised to STRL33 inhibited virus infection. We have cloned 12 envelope genes from the adapted MAL virus and 6 env genes from the adapted SIVmac239. We are currently returning these genes to the infectious molecular clones to assess their biological activities. Based on the cell tropism of a number of viruses, both SIV and HIV-1, we predicted the existence of another coreceptor on SUP-T1 cells. We have cloned this coreceptor and identified it as CCR9, a chemokine receptor for TECK (CCL25). CCR9 exists in two forms, A and B, that differ by 12 amino acids at the N terminus. CCR9B has activity with several strains of SIV, including SIVagmSAB and SIVagmTAN, but as yet no HIV-1 has been found that uses this molecule as an entry cofactor. Additional HIV-1 isolates including primary isolates are being screened. Since CCR9A/B is expressed in thymocytes and in the lymphocyte subset that trafficks to the gut, and because of the obvious importance of these tissues to HIV disease and AIDS pathogenesis, we are expanding our studies to include the coreceptors expressed in these cells as well as to the infection of these cells and of dendritic cells, which secrete CCL25 and thus may recruit T cells.