High-resolution profiling of linear B-cell epitopes from mucin-associated surface proteins (MASPs) of Trypanosoma cruzi during human infections.
High-resolution profiling of linear B-cell epitopes from mucin-associated surface proteins (MASPs) of Trypanosoma cruzi during human infections.
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DOI：
10.1371/journal.pntd.0005986
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发表时间：
2017-09
影响因子：
3.8
通讯作者：
Buscaglia CA
中科院分区：
文献类型：
--
作者：
Durante IM;La Spina PE;Carmona SJ;Agüero F;Buscaglia CA
克氏锥虫基因组具有编码粘蛋白相关表面蛋白（MASP）的基因和假基因的巨大家族。MASP分子显示“镶嵌”结构，具有高度保守的侧翼区和由大量短序列基序的不同组合组成的显著可变的中心和成熟结构域。MASP分子在T. cruzi，并且可能参与寄生虫-宿主相互作用和/或转移免疫应答。用慢性霍乱弧菌血清筛选由跨越232个非冗余MASP（总MASP含量的~25%）的整个序列的完全重叠的15聚体肽组成的高密度微阵列。该策略导致鉴定了86个抗原基序，每个基序可能代表单个线性B细胞表位，其被映射到69个不同的MASP。这些基序可以进一步分为31个结构上和可能的抗原相关序列的集群，并充分表征。与以前的报道相反，我们表明MASP抗原基序被限制在MASP多肽的中心和成熟区域，与它们的细胞内加工一致。这些基序的抗原性显示出与它们的基因组剂量和它们在MASP多肽内的相对位置显著正相关。此外，我们验证了MASP多肽内某些抗原基序的偏向性遗传共现，这与所提出的家族内重组事件相一致，所述家族内重组事件是其编码基因进化的基础。使用不同的合成/展示方法和大组血清样品进一步评估跨越7个MASP抗原基序的序列。总体而言，MASP抗原基序的血清学识别在T.克氏血清阳性人群，从而降低了它们在常规血清诊断中的适用性。如先前在体外和动物感染模型中观察到的，免疫特征支持在人感染期间几种MASP的同时表达。尽管它们在寄生虫生物学中的显著表达和潜在作用，本研究构成了来自T. cruzi MASPs在人类感染中的作用。锥虫属于一个古老的真核生物谱系，导致人类和牲畜的毁灭性疾病。克氏锥虫、布氏锥虫和大型利什曼原虫基因组的阐明为这些相关原生动物的研究奠定了里程碑。特别是T. cruzi，南美锥虫病的病原体，证明了可能参与寄生虫-宿主相互作用的基因家族的显著扩展和多样化。MASPs（粘蛋白相关表面蛋白）定义了第二大T。cruzi基因家族，具有约1400个编码参与寄生虫感染性和免疫逃避的表面糖蛋白的基因（和假基因）。MASP推导的产物在其N-和C-末端区域上携带高度保守的分选信号，所述分选信号将其引导并锚至寄生虫质膜。相反，中央和成熟的域，唯一一个显示在寄生虫表面上是惊人的变化，并表现出一个“马赛克样”的结构组成的一个大的剧目的短序列基序的不同组合。到目前为止，很少有研究分析MASP抗原性，并且它们使用低通量方法或动物感染模型进行。通过精密的肽微阵列技术和常规的血清学方法，我们在此提出了第一个无偏倚的，高通量的线性B细胞表位分析，从一个代表性的池（n = 232）的T。cruzi MASPs在人类感染中的作用。我们的研究结果进行了讨论，MASP的演变，表达谱和适用性在南美锥虫病血清学诊断。
The Trypanosoma cruzi genome bears a huge family of genes and pseudogenes coding for Mucin-Associated Surface Proteins (MASPs). MASP molecules display a ‘mosaic’ structure, with highly conserved flanking regions and a strikingly variable central and mature domain made up of different combinations of a large repertoire of short sequence motifs. MASP molecules are highly expressed in mammal-dwelling stages of T. cruzi and may be involved in parasite-host interactions and/or in diverting the immune response. High-density microarrays composed of fully overlapped 15mer peptides spanning the entire sequences of 232 non-redundant MASPs (~25% of the total MASP content) were screened with chronic Chagasic sera. This strategy led to the identification of 86 antigenic motifs, each one likely representing a single linear B-cell epitope, which were mapped to 69 different MASPs. These motifs could be further grouped into 31 clusters of structurally- and likely antigenically-related sequences, and fully characterized. In contrast to previous reports, we show that MASP antigenic motifs are restricted to the central and mature region of MASP polypeptides, consistent with their intracellular processing. The antigenicity of these motifs displayed significant positive correlation with their genome dosage and their relative position within the MASP polypeptide. In addition, we verified the biased genetic co-occurrence of certain antigenic motifs within MASP polypeptides, compatible with proposed intra-family recombination events underlying the evolution of their coding genes. Sequences spanning 7 MASP antigenic motifs were further evaluated using distinct synthesis/display approaches and a large panel of serum samples. Overall, the serological recognition of MASP antigenic motifs exhibited a remarkable non normal distribution among the T. cruzi seropositive population, thus reducing their applicability in conventional serodiagnosis. As previously observed in in vitro and animal infection models, immune signatures supported the concurrent expression of several MASPs during human infection. In spite of their conspicuous expression and potential roles in parasite biology, this study constitutes the first unbiased, high-resolution profiling of linear B-cell epitopes from T. cruzi MASPs during human infection. Trypanosomatids belong to an ancient eukaryotic lineage that cause devastating diseases in humans and livestock. The elucidation of the genomes of Trypanosoma cruzi, Trypanosoma brucei and Leishmania major established a landmark in the study of these relevant protozoa. In particular, the genome of T. cruzi, the agent of Chagas disease, evidenced a marked expansion and diversification of gene families likely involved in parasite-host interplay. MASPs (for mucin-associated surface proteins) define the second largest T. cruzi gene family, with ~1400 genes (and pseudogenes) coding for surface glycoproteins involved in parasite infectivity and immune evasion. MASP deduced products bear highly conserved sorting signals on their N- and C-terminal regions that direct and anchor them to the parasite plasma membrane. Conversely, the central and mature domain, the only one displayed on the parasite surface is strikingly variable and exhibit a ‘mosaic-like’ structure made up of different combinations of a large repertoire of short sequence motifs. Few studies have analyzed MASP antigenicity so far, and they were carried out using either low throughput approaches or animal infection models. By means of exquisite peptide micro-arrays technology followed by conventional serological methods we herein present the first non-biased, high-throughput profiling of linear B-cell epitopes from a representative pool (n = 232) of T. cruzi MASPs during human infection. Our findings are discussed in terms of MASP evolution, expression profile and applicability in Chagas disease serodiagnosis.
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影响因子：
1.5
作者：
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通讯作者：
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通讯作者：
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作者：
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