The Discovery of Novel Lipid and Protein Biomarkers of Lymphatic Filariasis

淋巴丝虫病（LF），又称象皮病，是一种由三种系统发育高度相关的线虫引起的寄生虫病：bancroffti乌氏丝虫病、马来布鲁氏丝虫病和蒂莫里布鲁氏丝虫病。LF被列为世界上最使人衰弱的被忽视的热带病之一，被认为是对公共卫生的主要威胁；据估计，50个国家有8亿人面临感染唇腭裂的风险，估计有5 100万人受到感染，同时有4 000万人因此毁容或致残。为了将LF作为一个公共卫生问题加以处理，世卫组织发起了消除LF全球规划。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（以大规模给药形式；MDA）的国家消除LF，这是新的2021-2030年NTD路线图的一部分。为阻断传播，消灭脊灰规划对所有高危人群实施了多轮平均5年的大规模预防接种。然而，与当前诊断相关的一些限制阻碍了NTD路线图的制定。这些限制包括：-寄生虫特异性抗体和抗原的持久性-目前用于诊断试验的抗体和抗原生物标志物，如Alere丝虫病试纸或Bm14快速试验，可在初次感染后持续数年。由于它们不能很容易地区分活动性感染和已解决感染，因此不必要地延迟了停止MDA的决定。-对早期感染不敏感-目前的检测不敏感或不针对幼虫期生物标志物，这可能会延迟对感染复发的发现，这在国家的监测阶段尤为重要。-与Loa Loa抗原的交叉反应性-一些L. Loa抗原通过共享碳水化合物表位与lf诊断单克隆抗体结合。这种交叉反应性是成功消灭LF的障碍，特别是在路易亚病流行地区。由于这些限制，迫切需要发现新的诊断性生物标志物，以检测早期感染，区分活跃感染和过去感染，并避免与其他丝虫病（如路易丝病）交叉反应。病原特异性脂质是鉴定疾病相关生物标志物的一个研究不足的来源。脂质生物标志物的发现虽然较新，但已在疟疾、肺结核等贫困疾病的诊断中得到应用。在新的基于蛋白质的生物标志物方面，研究已经开始定义马来芽孢杆菌的分泌组，最近的研究已经确定了当前诊断中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新的LF脂质和蛋白质生物标志物来解决当前诊断中面临的问题。在整个为期3年的项目中，需要解决的研究问题是：1)淋巴丝虫病寄生虫是否产生独特的脂质代谢物，是否可以在宿主循环中测量以检测活动性感染？2)去除糖基化的交叉反应性抗原是否会揭示新的特异性LF分泌蛋白抗原，为抗体检测的发展提供依据？

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?