Güvendi Mervenur, Can Hüseyin, Yavuz İrem, Özbilgin Ahmet, Değirmenci Döşkaya Aysu, Karakavuk Muhammet, Ün Cemal, Gürüz Adnan Yüksel, Yılmaz İsmail Cem, Gürsel Mayda, Gürsel İhsan, Döşkaya Mert
Department of Biology Molecular Biology Section, Faculty of Science, Ege University, İzmir, Türkiye.
Vaccine Development, Application and Research Center, Ege University, İzmir, Türkiye.
PLoS Negl Trop Dis. 2025 Jun 5;19(6):e0013137. doi: 10.1371/journal.pntd.0013137. eCollection 2025 Jun.
The surface of Leishmania spp. presents glycoprotein 63 (GP63), a metalloprotease that acts as one of the parasite's major antigens. A vaccine against leishmaniasis has not yet been developed and stationary phase promastigotes have utmost importance in transmitting Leishmania spp. from phlebotomine sand fly to humans or reservoirs. Therefore, this study aimed to analyze GP63 protein in three different Leishmania spp. to determine new vaccine candidate antigen against leishmaniasis using sequencing data of locally detected Leishmania strains and in silico approaches.
METHODOLOGY/PRINCIPAL FINDINGS: The GP63 protein sequences of the stationary phase/amastigote form of L. infantum, L. major, and L. tropica were identified and then the gene encoding GP63 protein in Leishmania positive samples (n:59) was amplified and sequenced for variation analysis. According to the results, 4, 6, 19 GP63 variants were found within L. infantum, L. major, and L. tropica isolates, respectively. The most prevalent variants within each species were selected for further analysis using in silico approaches. Accordingly, all selected GP63 proteins were antigenic and the amount of B and T cell epitopes were 23 for L. infantum, 10 for L. major, and 9 for L. tropica. The analysis of each epitope showed that all of them were non-toxic, non-allergen, and soluble but had different antigenicity values. Among these epitopes, EMEDQGSAGSAGS associated with L. major, STHDSGSTTC and AEDILTDEKRDILRK epitopes associated with L. infantum had the highest antigenicity values for B cell, MHC-I, and MHC-II epitopes, respectively. Moreover, conserved epitopes were detected among two or three Leishmania species.
CONCLUSIONS/SIGNIFICANCE: This study detected many epitopes that could be used in vaccine studies and the development of serological diagnostic assays.
利什曼原虫属的表面存在糖蛋白63（GP63），这是一种金属蛋白酶，是该寄生虫的主要抗原之一。尚未开发出针对利什曼病的疫苗，而静止期前鞭毛体在将利什曼原虫属从白蛉传播给人类或储存宿主方面至关重要。因此，本研究旨在分析三种不同利什曼原虫属中的GP63蛋白，利用本地检测到的利什曼原虫菌株的测序数据和计算机方法确定针对利什曼病的新疫苗候选抗原。
方法/主要发现：鉴定了婴儿利什曼原虫、硕大利什曼原虫和热带利什曼原虫静止期/无鞭毛体形式的GP63蛋白序列，然后对利什曼原虫阳性样本（n = 59）中编码GP63蛋白的基因进行扩增和测序以进行变异分析。根据结果，在婴儿利什曼原虫、硕大利什曼原虫和热带利什曼原虫分离株中分别发现了4、6、19种GP63变体。使用计算机方法选择每个物种中最普遍的变体进行进一步分析。因此，所有选定的GP63蛋白都具有抗原性，婴儿利什曼原虫的B细胞和T细胞表位数量为23个，硕大利什曼原虫为10个，热带利什曼原虫为9个。对每个表位的分析表明，它们均无毒、无过敏原且可溶，但具有不同的抗原性值。在这些表位中，与硕大利什曼原虫相关的EMEDQGSAGSAGS、与婴儿利什曼原虫相关的STHDSGSTTC和AEDILTDEKRDILRK表位分别对B细胞、MHC-I和MHC-II表位具有最高的抗原性值。此外，在两种或三种利什曼原虫物种中检测到了保守表位。
结论/意义：本研究检测到许多可用于疫苗研究和血清学诊断检测开发的表位。
