Centre for Medical Parasitology, Department of International Health, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
J Infect Dis. 2011 Jun 1;203(11):1679-85. doi: 10.1093/infdis/jir168.
Placental malaria infections are caused by Plasmodium falciparum-infected red blood cells sequestering in the placenta by binding to chondroitin sulfate A, mediated by VAR2CSA, a variant of the PfEMP1 family of adhesion antigens. Recent studies have shown that many P. falciparum genomes have multiple genes coding for different VAR2CSA proteins, and parasites with >1 var2csa gene appear to be more common in pregnant women with placental malaria than in nonpregnant individuals. We present evidence that, in pregnant women, parasites containing multiple var2csa-type genes possess a selective advantage over parasites with a single var2csa gene. Accumulation of parasites with multiple copies of the var2csa gene during the course of pregnancy was also correlated with the development of antibodies involved in blocking VAR2CSA adhesion. The data suggest that multiplicity of var2csa-type genes enables P. falciparum parasites to persist for a longer period of time during placental infections, probably because of their greater capacity for antigenic variation and evasion of variant-specific immune responses.
胎盘疟疾感染是由疟原虫感染的红细胞通过与硫酸软骨素 A 结合而在胎盘内被隔离引起的，这一过程由 VAR2CSA 介导，VAR2CSA 是 PfEMP1 家族黏附抗原的一种变体。最近的研究表明，许多疟原虫基因组都有多个编码不同 VAR2CSA 蛋白的基因，而且携带 >1 个 var2csa 基因的寄生虫在患有胎盘疟疾的孕妇中似乎比在非孕妇中更为常见。我们提供的证据表明，在孕妇中，携带多个 var2csa 型基因的寄生虫比携带单个 var2csa 基因的寄生虫具有选择性优势。在怀孕期间，var2csa 基因的多个拷贝的寄生虫的积累也与阻断 VAR2CSA 黏附的抗体的产生有关。这些数据表明，var2csa 型基因的多样性使疟原虫寄生虫能够在胎盘感染期间持续更长时间，可能是因为它们具有更大的抗原变异能力和逃避变体特异性免疫反应的能力。
