Vargas-Montes Mónica, Valencia-Jaramillo María Camila, Valencia-Hernández Juan David, Gómez-Marín Jorge Enrique, Arenas Ailan Farid, Cardona Néstor
Grupo de Estudio en Parasitología Molecular (GEPAMOL), Faculty of Health Sciences, Centro de Investigaciones Biomédicas, Universidad del Quindío, Quindio, Armenia, Colombia.
Faculty of Dentistry, Universidad Antonio Nariño, Quindio, Armenia, Colombia.
Med Microbiol Immunol. 2024 Dec 31;214(1):5. doi: 10.1007/s00430-024-00815-x.
Toxoplasma gondii infects approximately 30% of the population, and there is currently no approved vaccine. Identifying immunogenic peptides with high affinity to different HLA molecules is a promising vaccine strategy. This study used an in silico approach using artificial neural networks to identify T. gondii peptides restricted to HLA-A02, HLA-A24, and HLA-B35 alleles. Proteomes from seven T. gondii strains and transcriptomic data of overexpressed genes from T. gondii-RH in human PBMC were also used. Parasite protein sequences were analyzed with R 'Epitope Prediction' library. Peptide candidates were evaluated in the artificial neural networks based on the probabilities of output neurons (p > 0.5). The IFN-γ responses in PBMC from T. gondii seronegative and seropositive individuals were evaluated by ELISpot. Peptides with higher IFN-γ induction were evaluated to identify cytotoxic response in CD8 T cells (CD107a). In silico analysis identified 36 peptides from T. gondii proteins with predicted affinity to HLA-A02, A24, and B35 alleles. Experiments with PBMCs revealed that a peptide restricted to HLA-A02 (P1: FLFAWITYV) induced a significant increase in IFN-γ-producing cells (p = 0.004). For HLA-A24, a peptide (P8: VFAFAFAFFLI) also induced a significant IFN-γ response (p = 0.004), while for the HLA-B*35 allele, the P6 peptide (YPIAPSFAM) induced a response that differed significantly from the control (p = 0.05). These peptides induced also a significant percentage of central memory CD8 + T cells expressing the degranulation marker CD107a (p < 0.05). Finally, we identified three T. gondii peptides that induced IFN-γ response, and a cytotoxic response measured by CD107a expression on CD45RAneg-CD8 cells. These peptides could be considered part of a multi-epitope vaccine against toxoplasmosis in humans.
刚地弓形虫感染了约30%的人口，目前尚无获批的疫苗。鉴定与不同HLA分子具有高亲和力的免疫原性肽是一种很有前景的疫苗策略。本研究采用基于人工神经网络的计算机方法来鉴定受限于HLA-A02、HLA-A24和HLA-B35等位基因的刚地弓形虫肽。还使用了来自7种刚地弓形虫菌株的蛋白质组以及刚地弓形虫-RH在人外周血单个核细胞中过表达基因的转录组数据。用R语言的“表位预测”库分析寄生虫蛋白序列。基于输出神经元的概率（p>0.5）在人工神经网络中评估候选肽。通过酶联免疫斑点法评估刚地弓形虫血清阴性和血清阳性个体外周血单个核细胞中的IFN-γ反应。对诱导IFN-γ更高的肽进行评估，以确定CD8 T细胞（CD107a）中的细胞毒性反应。计算机分析从刚地弓形虫蛋白中鉴定出36种对HLA-A02、A24和B35等位基因具有预测亲和力的肽。外周血单个核细胞实验表明，一种受限于HLA-A02的肽（P1：FLFAWITYV）可使产生IFN-γ的细胞显著增加（p=0.004）。对于HLA-A24，一种肽（P8：VFAFAFAFFLI）也诱导了显著的IFN-γ反应（p=0.004），而对于HLA-B*35等位基因，P6肽（YPIAPSFAM）诱导的反应与对照有显著差异（p=0.05）。这些肽还诱导了相当比例的表达脱颗粒标记CD107a的中枢记忆CD8+T细胞（p<0.05）。最后，我们鉴定出三种诱导IFN-γ反应以及通过CD45RAneg-CD8细胞上CD107a表达测量的细胞毒性反应的刚地弓形虫肽。这些肽可被视为人类抗弓形虫病多表位疫苗的一部分。
