The Discovery of Novel Lipid and Protein Biomarkers of Lymphatic Filariasis

淋巴丝虫病（LF），也称为象皮病，是一种由三种系统发育高度相关的线虫引起的寄生虫病：班氏吴策丝虫、马来丝虫和帝汶丝虫。LF被认为是对公共卫生的主要威胁，因为它被列为全球最令人衰弱的被忽视的热带疾病之一;估计50个国家的8亿人面临感染LF的风险，估计有5100万人感染，而4000万人仍然因此而毁容或残疾。为解决LF这一公共卫生问题，世卫组织启动了消除LF全球计划。迄今为止，它们已在18个国家实现了消除，并使全球感染人数减少了74%。2020年，GPELF计划在至少80%使用预防性化疗（以大规模药物管理的形式; MDA）的国家消除LF，作为新的2021-2030 NTD路线图的一部分。为了阻断传播，LF根除方案对整个高危人群实施多轮MDA，平均为期5年。然而，有几个与当前诊断相关的限制阻碍了NTD路线图。这些限制包括：- 寄生虫特异性抗体和抗原的持久性-目前用于诊断测试的抗体和抗原生物标志物，如Alere丝虫病测试条或Bm 14快速测试，可以在初次感染后持续多年。由于他们不能很容易地区分活动性感染和已解决的感染，这不必要地推迟了停用MDA的决定。- 对早期感染不敏感-目前的检测方法对幼虫阶段的生物标志物不敏感或不针对幼虫阶段的生物标志物，这可能会延迟对感染复发的检测，而这在该国的监测阶段尤为重要。- 与Loa loa抗原的交叉反应性-几种Loa loa抗原。Loa抗原通过共有的碳水化合物表位与LF诊断性单克隆抗体结合。这种交叉反应性是成功消除LF的障碍，特别是在Loiasis流行地区。由于这些限制，迫切需要发现新的诊断生物标志物，可以检测早期感染，区分活动性和既往感染，并避免与其他丝虫病如丝虫病的交叉反应。病原体特异性脂质是用于鉴定疾病相关生物标志物的研究不足的来源。虽然脂质生物标志物的发现是新的，但它已被应用于疟疾和结核病等贫困疾病的诊断。在新的基于蛋白质的生物标志物方面，研究已经开始定义B的分泌组。Malayi，并且最近的研究已经确定了在当前诊断中引起交叉反应性问题的聚糖部分的性质。因此，该项目的目的是通过发现LF的新脂质和蛋白质生物标志物来解决当前诊断中面临的问题。在整个3年的项目中要回答的研究问题是：1）淋巴丝虫寄生虫产生的独特脂质代谢物，以及它们是否可以在宿主的循环中进行测量，以检测活动性感染？2)糖基化交叉反应抗原的去除是否会揭示用于抗体检测开发的新型和特异性LF分泌蛋白抗原？

Lymphatic filariasis (LF), also known as elephantiasis, is a parasitic disease caused by three phylogenetically highly related nematode worms: Wuchereria bancrofti, Brugia malayi and Brugia timori. LF is considered a major threat to public health as its classified as one of the most debilitating neglected tropical diseases worldwide; an estimated 800 million people across 50 countries are at risk of contracting LF, an estimated 51 million people are infected whilst 40 million remain disfigured or disabled as a result. To tackle LF as a public health concern, WHO launched the Global programme to Eliminate LF (GPELF). To date, they have achieved elimination in 18 countries and have reduced the number of global infections by 74%. In 2020, the GPELF set out to eliminate LF in at least 80% of countries using preventative chemotherapy (in the form of mass drug administration; MDA) as part of the new 2021-2030 NTD road map. To interrupt transmission, LF eradication programmes administer multiple rounds of MDA for an average of 5 years to the entire at-risk population. However, there are several limitations associated with current diagnostics that are hindering the NTD road map. These limitations include: - The persistence of parasite-specific antibodies and antigens - current antibody and antigen biomarkers used in diagnostic tests, such as Alere filariasis test strip or the Bm14 rapid test, can persist for years after the initial infection. Since they cannot readily distinguish between active infections from resolved infections, it unnecessarily delays the decision to stop MDA. - Insensitivity against early-stage infections- current tests are insensitive of not directed at larval-stage biomarkers which can delay the detection of recrudescence of infection, which is particularly important during the country's surveillance phase. - Cross reactivity with Loa loa antigens - several L. loa antigens have been implicated in binding to LF-diagnostic monoclonal antibodies via shared carbohydrate epitopes. This cross reactivity is an impediment to the successful elimination of LF, particularly in loiasis-endemic regions. Due to these limitations, there is an urgent need to discover new diagnostic biomarkers that can detect early-stage infections, differentiate between active and past infections, and avoid cross-reactivity with other filarial diseases such as loiasis. Pathogen-specific lipids are an under-studied source for the identification of disease-related biomarkers. Although lipid biomarker discovery is new, it has been applied in the diagnosis of diseases of poverty such as malaria and tuberculosis. In terms of novel protein-based biomarkers, research has started to define the secretome of B. malayi, and recent studies have determined the nature of glycan moieties responsible for cross-reactivity issues in current diagnostics. Therefore, the aim of this project is to address the issues faced in current diagnostics by discovering new lipid and protein biomarkers of LF. The research questions to be answered throughout the 3-year project are:1) Are unique lipid metabolites produced by lymphatic filarial parasites and can they be measured in the circulation of the host for the purposes of detecting active infections?2) Will removal of glycosylated cross-reactive antigens reveal novel and specific LF secreted protein antigens for antibody detection development?