Souza-Silva Flávia A, Torres Letícia M, Santos-Alves Jessica R, Tang Michaelis Loren, Sanchez Bruno A M, Sousa Tais N, Fontes Cor J F, Nogueira Paulo A, Rocha Roberto S, Brito Cristiana F A, Adams John H, Kano Flora S, Carvalho Luzia H
Laboratório de Malária, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, MG, Brasil.
Universidade Federal de Mato Grosso, campus Sinop, Sinop, MT, Brasil.
PLoS One. 2014 Apr 7;9(4):e93782. doi: 10.1371/journal.pone.0093782. eCollection 2014.
The Plasmodium vivax Duffy binding protein (PvDBP) and its erythrocytic receptor, the Duffy antigen receptor for chemokines (DARC), are involved in the major P. vivax erythrocyte invasion pathway. An open cohort study to analyze DARC genotypes and their relationship to PvDBP immune responses was carried out in 620 volunteers in an agricultural settlement of the Brazilian Amazon. Three cross-sectional surveys were conducted at 6-month intervals, comprising 395, 410, and 407 subjects, respectively. The incidence rates of P. vivax infection was 2.32 malaria episodes per 100 person-months under survey (95% confidence interval [CI] of 1.92-2.80/100 person-month) and, of P. falciparum, 0.04 per 100 person-months (95% CI of 0.007-0.14/100 person-month). The distribution of DARC genotypes was consistent with the heterogeneous ethnic origins of the Amazon population, with a predominance of non-silent DARC alleles: FYA > FYB. The 12-month follow-up study demonstrated no association between DARC genotypes and total IgG antibodies as measured by ELISA targeting PvDBP (region II, DBPII or regions II-IV, DBPII-IV). The naturally acquired DBPII specific binding inhibitory antibodies (BIAbs) tended to be more frequent in heterozygous individuals carrying a DARC-silent allele (FY*BES). These results provide evidence that DARC polymorphisms may influence the naturally acquired inhibitory anti-Duffy binding protein II immunity.
间日疟原虫达菲结合蛋白（PvDBP）及其红细胞受体趋化因子达菲抗原受体（DARC）参与间日疟原虫主要的红细胞入侵途径。在巴西亚马逊地区一个农业定居点的620名志愿者中开展了一项开放性队列研究，以分析DARC基因型及其与PvDBP免疫反应的关系。每隔6个月进行3次横断面调查，分别包括395、410和407名受试者。在调查期间，间日疟原虫感染发病率为每100人月2.32次疟疾发作（95%置信区间[CI]为1.92 - 2.80/100人月），恶性疟原虫为每100人月0.04次（95%CI为0.007 - 0.14/100人月）。DARC基因型的分布与亚马逊地区人群的种族异质性一致，非沉默DARC等位基因占优势：FYA > FYB。为期12个月的随访研究表明，通过酶联免疫吸附测定法（ELISA）检测针对PvDBP（区域II，DBPII或区域II - IV，DBPII - IV）的DARC基因型与总IgG抗体之间无关联。在携带DARC沉默等位基因（FY*BES）的杂合个体中，自然获得的DBPII特异性结合抑制抗体（BIAbs）往往更为常见。这些结果证明，DARC多态性可能会影响自然获得的抗达菲结合蛋白II抑制性免疫。
