ANALYSIS OF T CELL RESPONSES IN HUMAN LEISHMANIASIS

人类利什曼病 T 细胞反应分析

• 批准号: 6431576
• 负责人: David Sacks
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6431576
• 关键词: Macaca mulatta; Psychodidae; T lymphocyte; cellular immunity; enzyme linked immunosorbent assay; flow cytometry; gastrointestinal disorder; host organism interaction; human tissue; interferon gamma; interleukin 12; laboratory mouse; leishmaniasis; macrophage; microorganism immunology; nonhuman therapy evaluation; protozoal vaccine; tissue /cell culture; tumor necrosis factor alpha; vaccine development

We previously established a model of cutaneous leishmaniasis due to L. major infection combining two main features of natural transmission; inoculation of a low number of metacyclic promastigotes into the mouse ear dermis. In this model, the evolution of small, healing dermal lesions occurs in three distinct phases that have not been appreciated before: 1) an initial ?silent? phase, lasting 4-5 wks, favoring the establishment of the peak load of parasites in the dermis in the absence of lesion formation; 2) an acute phase, lasting 5-10 wks, corresponding to the development and resolution of a lesion that is associated with an acute infiltration of neutrophils, macrophages, and eosinophils into the dermis, and is coincident with the onset of immunity and the killing of parasites in the site; and 3) a chronic phase, lasting for the life of the animal, during which a low number of parasites persist in the skin in the absence of overt pathology. Adaptive immunity in this model confirmed a role for Th1 cells, and in addition revealed a requirement for CD8+ T cells, based on the results obtained in ?2 microglobulin KO mice, CD8 KO mice, and CD8 depleted mice, which in each case failed to control infection in the skin. The conditions favoring the persistence of low numbers of parasites in the skin following healing have also been studied. The chronic site is characterized by a high number of both CD8+ and CD4+ T lymphocytes in the dermis that are able to produce IFN g in response to the antigen. In vivo treatment with either anti-IFNg, anti-CD4+, or anti-CD8+ antibodies resulted in a dramatic increase in parasite numbers and reactivation of dermal lesions. Thus IFNg pressure is necessary to maintain a low parasite burden but not sufficient to clear it. The persistence of the parasite depends upon the production of IL-10 in the site, as evidenced by a) the presence of IL-10 staining cells in the ear and draining lymph node, b) treatment with anti-IL-10R antibodies resulted in complete clearance of parasites from the skin, and c) the complete clearance of L. major from the skin in IL-10 KO and IL-4/IL-10 KO mice. The low dose, intradermal infection model has been extended to L. tropica, which is responsible for anthroponotic cutaneous leishmaniasis. While the growth of the parasite is contained, there is no dermal pathology, parasite clearance does not occur, and a transmissible level of parasitemia persists in the skin for the life of the animal. This equilibrium was again found to be established by counter-balanced levels of IFNg and IL-10. The chronic infections due to L. tropica were cleared from the skin in IL-10 deficient mice, and in mice treated with anti-IL-10R antibodies. The natural challenge model was used to compare the potency and durability of vaccination with a cocktail of plasmid DNAs encoding the antigens LACK, M15, and MAPS, with that of heat killed promastigotes plus recombinant IL-12 (rIL-12). While both vaccines conferred complete protection against dermal leishmaniasis , this protection lasted longer in the DNA vaccinated mice. Furthermore, only the DNA vaccine reduced the parasitic burden in the skin during the acute and chronic stages to the low levels achieved in healed mice, and only the DNA vaccine eliminated the capacity of challenged mice to serve as infection reservoirs for vector sand flies. The clinical forms of leishmaniasis in humans range from self-healing cutaneous lesions to often fatal visceral disease. These diverse clinical outcomes are attributed primarily to differences in the Leishmania species initiating the infections. Animal models using a species associated with self-limiting cutaneous disease, L. major, have revealed that protective immunity requires CD40/CD40L-dependent, IL-12-driven Th1 responses. We have found that in contrast to L. major, Leishmania species responsible for visceral disease (L dononvani), as well as species associated with persistent, cutaneous lesions and occasional systemic disease (L. tropica), do not prime human dendritic cells for CD40L induced IL-12p70 production, and these intrinsic differences in parasite interactions with DC may account, at least in part, for the evolution of healing and non-healing forms of leishmanial disease.

我们以前建立了一个由L.主要感染结合自然传播的两个主要特征;将少量的后环前鞭毛体接种到小鼠耳真皮中。在这个模型中，小的，愈合的皮肤损伤的演变发生在三个不同的阶段，以前没有得到赞赏：1）初始？沉默？阶段，持续4-5周，有利于在没有损伤形成的情况下在真皮中建立寄生虫的峰值负荷; 2）急性期，持续5-10周，对应于与嗜中性粒细胞、巨噬细胞和嗜酸性粒细胞向真皮中的急性浸润相关的病变的发展和消退，并且与免疫的开始和该部位寄生虫的杀死同时发生;和3）慢性期，持续动物的一生，在此期间，少量寄生虫在皮肤中持续存在，而没有明显的病理学。 在这个模型中的适应性免疫证实了Th 1细胞的作用，此外还揭示了CD 8 + T细胞的要求，根据在？2微球蛋白KO小鼠、CD 8 KO小鼠和CD 8耗尽小鼠，其在每种情况下都不能控制皮肤中的感染。 还研究了有利于愈合后皮肤中少量寄生虫持续存在的条件。慢性部位的特征在于真皮中大量的CD 8+和CD 4 + T淋巴细胞，其能够响应于抗原产生IFN γ。 用抗IFNg、抗CD 4+或抗CD 8+抗体的体内治疗导致寄生虫数量的急剧增加和皮肤病变的再活化。因此IFNg压力对于维持低寄生虫负荷是必需的，但不足以清除寄生虫。寄生虫的持续存在取决于该部位中IL-10的产生，如以下所证明的：a）耳和引流淋巴结中存在IL-10染色细胞，B）用抗IL-10 R抗体处理导致寄生虫从皮肤完全清除，c）L.主要来自IL-10 KO和IL-4/IL-10 KO小鼠的皮肤。 低剂量皮内感染模型已推广到L.热带，这是人类皮肤利什曼病的原因。 虽然寄生虫的生长受到控制，但没有皮肤病理学，寄生虫清除不会发生，并且在动物的一生中，皮肤中持续存在可传播水平的寄生虫血症。 再次发现这种平衡通过IFNg和IL-10的平衡水平建立。 L.在IL-10缺陷小鼠和用抗IL-10 R抗体处理的小鼠中，从皮肤上清除tropica。使用自然攻击模型比较用编码抗原LACK、M15和MAPS的质粒DNA的混合物接种的效力和耐久性，以及热灭活前鞭毛体加重组IL-12（rIL-12）的效力和耐久性。虽然这两种疫苗都能完全保护小鼠免受皮肤利什曼病的侵害，但这种保护作用在DNA疫苗接种的小鼠中持续时间更长。 此外，只有DNA疫苗在急性和慢性阶段将皮肤中的寄生虫负担降低到治愈小鼠中达到的低水平，并且只有DNA疫苗消除了受攻击小鼠作为媒介白蛉感染宿主的能力。人类利什曼病的临床形式从自愈性皮肤损伤到通常致命的内脏疾病不等。 这些不同的临床结果主要归因于引发感染的利什曼原虫种属的差异。使用与自限性皮肤病相关的物种，L。主要的研究表明，保护性免疫需要CD 40/CD 40 L依赖性、IL-12驱动的Th 1应答。我们发现，与L.主要的利什曼原虫属物种负责内脏疾病（杜氏利什曼原虫），以及与持续性皮肤病变和偶尔的全身性疾病相关的物种（利什曼原虫）。tropica），不为CD 40 L诱导的IL-12 p70产生而引发人树突细胞，并且寄生虫与DC相互作用的这些内在差异可以至少部分地解释利什曼病的愈合和非愈合形式的演变。