Lasso Paola, Beltrán Lina, Guzmán Fanny, Rosas Fernando, Thomas M Carmen, López Manuel Carlos, González John Mario, Cuéllar Adriana, Puerta Concepción J
Laboratorio de Parasitología Molecular, Pontificia Universidad Javeriana, Bogotá, Colombia.
Grupo de Inmunobiología y Biología Celular, Pontificia Universidad Javeriana, Bogotá, Colombia.
PLoS One. 2016 Mar 14;11(3):e0150996. doi: 10.1371/journal.pone.0150996. eCollection 2016.
TcTLE is a nonamer peptide from Trypanosoma cruzi KMP-11 protein that is conserved among different parasite strains and that is presented by different HLA-A molecules from the A2 supertype. Because peptides presented by several major histocompatibility complex (MHC) supertypes are potential targets for immunotherapy, the aim of this study was to determine whether MHC molecules other than the A2 supertype present the TcTLE peptide.
METHODOLOGY/PRINCIPAL FINDINGS: From 36 HLA-A2-negative chagasic patients, the HLA-A genotypes of twenty-eight patients with CD8+ T cells that recognized the TcTLE peptide using tetramer (twenty) or functional (eight) assays, were determined. SSP-PCR was used to identify the A locus and the allelic variants. Flow cytometry was used to analyze the frequency of TcTLE-specific CD8+ T cells, and their functional activity (IFN-γ, TNFα, IL-2, perforin, granzyme and CD107a/b production) was induced by exposure to the TcTLE peptide. All patients tested had TcTLE-specific CD8+ T cells with frequencies ranging from 0.07-0.37%. Interestingly, seven of the twenty-eight patients had HLA-A homozygous alleles: A24 (5 patients), A23 (1 patient) and A01 (1 patient), which belong to the A24 and A1 supertypes. In the remaining 21 patients with HLA-A heterozygous alleles, the most prominent alleles were A24 and A68. The most common allele sub-type was A2402 (sixteen patients), which belongs to the A24 supertype, followed by A6802 (six patients) from the A2 supertype. Additionally, the A3002/A*3201 alleles from the A1 supertype were detected in one patient. All patients presented CD8+ T cells producing at least one cytokine after TcTLE peptide stimulation.
CONCLUSION/SIGNIFICANCE: These results show that TcTLE is a promiscuous peptide that is presented by the A24 and A1 supertypes, in addition to the A2 supertype, suggesting its potential as a target for immunotherapy.
TcTLE是一种来自克氏锥虫KMP-11蛋白的九聚体肽，在不同寄生虫菌株中保守，并由A2超型的不同HLA-A分子呈递。由于几种主要组织相容性复合体（MHC）超型呈递的肽是免疫治疗的潜在靶点，本研究的目的是确定除A2超型之外的MHC分子是否呈递TcTLE肽。
方法/主要发现：从36名HLA-A2阴性恰加斯病患者中，确定了28名使用四聚体（20名）或功能分析（8名）识别TcTLE肽的CD8+T细胞患者的HLA-A基因型。使用序列特异性引物聚合酶链反应（SSP-PCR）鉴定A位点和等位基因变体。流式细胞术用于分析TcTLE特异性CD8+T细胞的频率，并且通过暴露于TcTLE肽诱导其功能活性（干扰素-γ、肿瘤坏死因子α、白细胞介素-2、穿孔素、颗粒酶和CD107a/b产生）。所有测试患者均有TcTLE特异性CD8+T细胞，频率范围为0.07 - 0.37%。有趣的是，28名患者中有7名具有HLA-A纯合等位基因：A24（5名患者）、A23（1名患者）和A01（1名患者），它们属于A24和A1超型。在其余21名具有HLA-A杂合等位基因的患者中，最突出的等位基因是A24和A68。最常见的等位基因亚型是属于A24超型的A2402（16名患者），其次是来自A2超型的A6802（6名患者）。此外，在一名患者中检测到来自A1超型的A3002/A*3201等位基因。所有患者在TcTLE肽刺激后均呈现产生至少一种细胞因子的CD8+T细胞。
结论/意义：这些结果表明，除了A2超型之外，TcTLE是一种由A24和A1超型呈递的多反应性肽，表明其作为免疫治疗靶点的潜力。
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