Innate Immunity Genes In HIV-1 Transmission

这个新项目是我们之前工作的延伸，该工作证明了先天免疫和toll样受体（TLR）在肺对环境污染物的反应中起关键作用。（该研究已在约翰霍普金斯大学进行，并将转移到NIEHS。）已知tlr是先天免疫的重要调节剂，是抵抗HIV感染和艾滋病进展的关键组成部分。TLR4介导小鼠和人类对革兰氏阴性细菌（如脂多糖或内毒素）的反应，也被认为是体外HIV感染和病毒复制的决定因素。我们在研究中验证了两个假设：(1)TLR4的功能多态性与HIV-1感染呈负相关；(2) TLR4多态性赋予hiv感染者对疾病进展的抵抗力。与多中心艾滋病队列研究（MACS）合作，我们获得了501名男性的DNA样本并进行了检测：402名HIV感染者（病例）和99名高危HIV阴性男性（对照组）。在感染者中，379人的HIV血清转化窗口小于1年，艾滋病发病窗口小于1年（定义明确的病例）。通过单链构象多态性（SSCP）分析个体对内毒素产生抗性的896个A to G （Asp299Gly）和1190个A to G (Thr399Ile) TLR4多态性进行基因分型。序列分析证实了多态性。为了验证第一种假设（HIV传播），我们比较了病例和对照组之间TLR4突变的患病率。为了验证第二个假设（艾滋病进展），对379例明确定义的病例进行了血清转化为艾滋病的时间和血清转化后CD4、CD8和HIV RNA的动力学评估。我们发现任何TLR4基因型在HIV阴性和阳性男性之间的HIV传播没有差异，因此表明TLR4多态性与HIV传播无关。然而，与野生型等位基因纯合（+/+）的男性相比，TLR4多态性杂合（+/-）或纯合（-/-）的男性在血清转化后的前8年内对艾滋病发作有显著的保护作用（RR=0.44, 95% CI=0.21-0.89）。有趣的是，任何一种多态性纯合的男性（Asp299Gly, n=3; Thr399Ile, n=4）都没有患上艾滋病（最低随访时间为10.7年）。与+/-和+/+男性相比，-/-男性血清转化后的HIV RNA中位数较低，但数量少，无法进行正式分析。因此，我们的研究结果表明，TLR4是hiv感染者艾滋病进展的重要决定因素，可能为治疗艾滋病提供潜在的治疗靶点。

This new project was started as an extension of our previous work that demonstrated a critical role of innate immunity and toll-like receptors (TLR) in pulmonary responses to environmental pollutants. (It has been conducted at Johns Hopkins and will be transferred to NIEHS.) TLRs are known to be important modulators of innate immunity, a critical component of resistance to HIV infection and AIDS progression. TLR4, which mediates responses to Gram-negative bacteria (e.g. lipopolysaccharide or endotoxin) in mouse and humans, has also been implicated as a determinant of HIV infection and viral replication in vitro. We have tested two hypotheses in our study: (1) functional polymorphisms in TLR4 negatively associate with HIV-1 infection; (2) the TLR4 polymorphism confers resistance to disease progression in HIV-infected individuals. In collaboration with the multi-center AIDS cohort study (MACS), we obtained and tested DNA specimens from 501 men: 402 HIV seroconverters (cases) and 99 high-risk HIV negative men (controls). Among seroconverters, 379 had a HIV seroconversion window less <1 yr and AIDS onset window <1 yr (well-defined cases). Individuals were genotyped by single-stranded conformation polymorphism (SSCP) analysis for 896 A to G (Asp299Gly) and 1190 A to G (Thr399Ile) TLR4 polymorphisms that confer resistance to endotoxin. Polymorphisms were confirmed by sequence analysis. To test the first hypothesis (HIV transmission), we compared prevalence of the TLR4 mutations between cases and controls. To test the second hypothesis (AIDS progression), time from seroconversion to AIDS and kinetics of CD4, CD8, and HIV RNA following seroconversion were assessed for the 379 well-defined cases. We found no differences in HIV transmission between HIV negative and positive men for any of the TLR4 genotypes, therefore indicating that the TLR4 polymorphisms were not associated with HIV transmission. However, men heterozygous (+/-) or homozygous (-/-) for the TLR4 polymorphism had significant protection against AIDS onset during the first 8 yr following seroconversion (RR=0.44, 95% CI=0.21-0.89) compared with men homozygous for the wild-type allele (+/+). Interestingly, all men homozygous for either polymorphism (Asp299Gly, n=3; Thr399Ile, n=4) did not develop AIDS (minimum follow up = 10.7 yr). Median HIV RNA following seroconversion was lower in -/- men compared to +/- and +/+ men, but small numbers precluded formal analysis. Our results therefore indicate TLR4 is an important determinant of AIDS progression in HIV-infected individuals, and may provide a potential therapeutic target for treatment of AIDS.