HIV suppression by Beta-defensins

描述（由申请人提供）：β-防御素是小的（大小为3- 5 Kd）分泌蛋白，是先天免疫的组分;一些是组成型表达的，如人β-防御素（HBD）-1，而其他如hBD 2和-3，可由细胞因子或其他免疫应答刺激物诱导。β-防御素主要由上皮细胞和嗜中性粒细胞分泌，尽管在T和NK细胞中也观察到它们的分泌，并且最初它们被描述为抗微生物蛋白;最近的研究表明它们也充当化学引诱物。它们的表达在口腔、舌、消化器官的上皮中升高，并且还在气道、乳腺、肝脏和其他器官中升高。特别是，β-防御素存在于唾液中，并且这些蛋白质的浓度在口腔中可以非常高，在舌中100 μ m厚的层中测得的局部浓度高达100 μ g/ml。因此，β-防御素作为先天免疫的重要组成部分，控制着口腔感染的发生。β-防御素的抗微生物活性是由于其透化细菌膜的能力。总之，这些信息表明β-防御素可以提供一种针对口服HIV感染的先天免疫形式，可以用于抗HIV预防。与此一致，我们的初步数据表明，选择β-防御素，特别是hBD 2，抑制R5 HIV感染的剂量依赖性的方式，在剂量是兼容的或低于在口腔中测量。此外，我们的研究表明，hBD 2直接治疗病毒降低了HIV感染。这种抗病毒活性让人想起最近报道的α防御素的HIV抑制特性。然而，只有β-防御素以HIV抑制浓度天然存在于口腔中。因此，我们的中心假设是，β-防御素介导和抗逆转录病毒机制，基于抑制病毒进入，在口腔中，能够防止口腔HIV传播。 因此，我们建议a）表征hBD 2抑制哪些HIV- 1表型。这些实验将确定hBD 2的广泛抑制作用，以及其体内抑制作用机制是否B）决定hBD 2对HIV-1生命周期中事件的影响。在这个目标中，我们将检查和比较hBD 2对HIV进入/融合和病毒复制的细胞内步骤的影响。 阐明HIV感染和表达中受hBD 2影响的事件将允许对其作用机制的彻底研究和结构-功能研究，从而为新的抗病毒治疗和预防策略提供基础。最后，这些研究将有助于理解先天免疫在口腔中的作用。

DESCRIPTION (provided by applicant): beta-Defensins are small (3-5Kd in size) secreted proteins that are components of innate immunity; some are constitutively expressed, such as human beta-defensin (HBD)-1, while others, like hBD2 and -3, are inducible by cytokines or other immune response stimuli. beta-defensins are secreted preeminently by epithelial cells, and by neutrophil cells, although their secretion has been observed also in T and NK cells, and initially they were described as antimicrobial proteins; recent research has indicated that they also act as chemoattractants. Their expression is elevated in the epithelia of the mouth, tongue, digestive apparatus, and also in airways, mammary gland, liver and other organs. In particular, beta-defensins are present in saliva, and the concentration of these proteins can be very high in the oral cavity, with measured local concentration as high as 100mu g/ml, in a 100mu m-thick layer in the tongue. Therefore, it appears that beta-defensins, as important component of the innate imniunity, control the occurrence of infections in the oral cavity. The antimicrobial activity of beta-defensins is due to their ability to permeabilize bacterial membranes. Taken together, this information indicates that beta-defensins could provide a form of innate immunity against oral HIV infection that might be exploited for anti-HIV prophylaxis. In agreement, our preliminary data show that select beta-defensins, especially hBD2, inhibit R5 HIV infection in a dose dependent manner, at doses that are compatible with or below those measured in the oral cavity. In addition, our studies show that hBD2 treatment directly on the virus lowers HIV infection. This antiviral activity is reminiscent of the recently reported HIV suppressive properties of alpha defensins. However, only beta-defensins are naturally present in the oral cavity at HIV-suppressive concentrations. Therefore, our central hypothesis is that beta-defensins mediate and antiretroviral mechanism, based on inhibition of viral entry, in the oral cavity that is capable of preventing oral HIV transmission. Accordingly, we propose to a) characterize which HIV- 1 phenotypes are suppressed by hBD2. These experiments will define the broad suppressive effects of hBD2 and whether its mechanism of suppression functions in vivo b) determine the effects of hBD2 on events in the HIV-1 life cycle. In this aim we will examine and compare the effects of hBD2 on HIV entry/fusion and on intracellular steps of viral replication. The elucidation of the event(s) in HIV infection and expression that are affected by hBD2 will allow for a thorough study of its mechanism of action and for structure-function studies, thus proving basis for novel antiviral therapeutic and preventive strategies. Finally, these studies will constitute a contribution towards the understanding of the role of innate immunity in the oral cavity.