The Plasmodium vivax Cysteine-Rich Protective Antigen (PvCyRPA) has an important role in erythrocyte invasion and has been considered a target for vivax malaria vaccine development. Nonetheless, its genetic diversity remains uncharted in Brazilian malaria-endemic areas. Therefore, we investigated the pvcyrpa genetic polymorphism in 98 field isolates from the Brazilian Amazon and its impact on the antigenicity of predicted B-cell epitopes. Genetic diversity parameters, population genetic analysis, neutrality test and the median-joining network were analyzed, and the potential amino acid polymorphism participation in B-cell epitopes was investigated. One synonymous and 26 non-synonymous substitutions defined fifty haplotypes. The nucleotide diversity and Tajima’s D values varied across the coding gene. The exon-1 sequence had greater diversity than those of exon-2. Concerning the prediction analysis, seven sequences were predicted as linear B cell epitopes, the majority contained in conformational epitopes. Moreover, important amino acid polymorphism was detected in regions predicted to contain residues participating in B-cell epitopes. Our data suggest that the pvcyrpa gene presents a moderate polymorphism in the studied isolates and such polymorphisms alter amino acid sequences contained in potential B cell epitopes, an important observation considering the antigen potentiality as a vaccine candidate to cover distinct P. vivax endemic areas worldwide.

中文翻译：

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巴西亚马逊地区五个不同地区田间分离株间日疟原虫富含半胱氨酸的保护性抗原 (PvCyRPA) 的遗传多样性

间日疟原虫富含半胱氨酸的保护性抗原 (PvCyRPA) 在红细胞侵袭中具有重要作用，并被认为是间日疟疫苗开发的目标。尽管如此，它的遗传多样性在巴西疟疾流行地区仍然未知。因此，我们研究了pvcyrpa来自巴西亚马逊地区的 98 个田间分离株的遗传多态性及其对预测的 B 细胞表位抗原性的影响。对遗传多样性参数、群体遗传分析、中性检验和中值连接网络进行分析，探讨氨基酸多态性参与B细胞表位的可能性。1 个同义替换和 26 个非同义替换定义了 50 个单倍型。核苷酸多样性和 Tajima 的 D 值因编码基因而异。外显子 1 序列比外显子 2 具有更大的多样性。关于预测分析，7个序列被预测为线性B细胞表位，大部分包含在构象表位中。此外，在预测含有参与 B 细胞表位的残基的区域中检测到重要的氨基酸多态性。pvcyrpa基因在所研究的分离物中呈现出中度多态性，并且这种多态性改变了潜在 B 细胞表位中包含的氨基酸序列，考虑到抗原潜力作为覆盖全球不同间日疟原虫流行地区的候选疫苗，这是一个重要的观察结果。