Identity of <i>S</i>. <i>haematobium</i> TAL proteins.

Schistosoma haematobium is the most prevalent of the human-infecting schistosome species, causing significant morbidity in endemically exposed populations. Despite this, it has been relatively understudied compared to its fellow species, S. mansoni. Here we provide the first comprehensive characterization of the S. haematobium Tegument Allergen-Like protein family, a key protein family directly linked to protective immunity in S. mansoni infection. Comparable with observations for S. mansoni, parasite phylogenetic analysis and relative gene expression combined with host serological analysis support a cross-reactive relationship between S. haematobium TAL proteins, exposed to the host immune system as adult worms die, and closely related proteins, exposed during penetration by the infecting cercarial and early schistosomulae stages. Specifically, our results strengthen the evidence for host immunity driven by cross-reactivity between family members TAL3 and TAL5, establishing it for the first time for S. haematobium infection. Furthermore, we build upon this relationship to include the involvement of an additional member of the TAL protein family, TAL11 for both schistosome species. Finally, we show a close association between experience of infection and intensity of transmission and the development of protective IgE responses to these antigens, thus improving our knowledge of the mechanisms by which protective host immune responses develop. This knowledge will be critical in understanding how control efforts such as mass drug administration campaigns influence the development of host immunity and subsequent patterns of infection and disease within endemic populations.埃及血吸虫（Schistosoma haematobium）是感染人类的血吸虫物种中流行率最高的种类，在地方性流行地区的暴露人群中可引发严重的发病负担。尽管如此，相较于其同属物种曼氏血吸虫（S. mansoni），针对埃及血吸虫的研究仍相对匮乏。本研究首次对埃及血吸虫被膜过敏原样（Tegument Allergen-Like, TAL）蛋白家族完成全面表征——该蛋白家族是与曼氏血吸虫感染中的保护性免疫直接相关的关键蛋白家族。与曼氏血吸虫的相关研究发现一致，本研究通过寄生虫系统发育分析、相对基因表达分析结合宿主血清学分析，证实埃及血吸虫TAL蛋白与亲缘关系密切的蛋白之间存在交叉反应关系：前者在成虫死亡时暴露于宿主免疫系统，后者则在感染性尾蚴侵入宿主及早期童虫阶段暴露。具体而言，本研究结果进一步巩固了TAL3与TAL5家族成员间的交叉反应所介导的宿主免疫机制的相关证据，并首次在埃及血吸虫感染中确立了该机制。此外，本研究拓展了该蛋白家族的关联范围，将TAL蛋白家族的另一成员TAL11纳入两种血吸虫的交叉反应研究范畴。本研究最终证实，感染暴露经历、传播强度与针对这些抗原的保护性IgE应答的产生之间存在紧密关联，从而加深了我们对保护性宿主免疫应答形成机制的认知。此类认知对于理解大规模药物治疗等防控措施如何影响宿主免疫发育，以及地方性流行人群后续的感染与疾病模式，均具有关键指导意义。