Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia ; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia.
PLoS One. 2013 Sep 9;8(9):e74627. doi: 10.1371/journal.pone.0074627. eCollection 2013.
Naturally acquired humoral immunity to the malarial parasite Plasmodium falciparum can protect against disease, although the precise mechanisms remain unclear. Although antibody levels can be measured by ELISA, few studies have investigated functional antibody assays in relation to clinical outcomes. In this study we applied a recently developed functional assay of antibody-mediated opsonisation of merozoites, to plasma samples from a longitudinal cohort study conducted in a malaria endemic region of Papua New Guinea (PNG). Phagocytic activity was quantified by flow cytometry using a standardized and high-throughput protocol, and was subsequently evaluated for association with protection from clinical malaria and high-density parasitemia. Opsonising antibody responses were found to: i) increase with age, ii) be enhanced by concurrent infection, and iii) correlate with protection from clinical episodes and high-density parasitemia. Stronger protective associations were observed in individuals with no detectable parasitemia at baseline. This study presents the first evidence for merozoite phagocytosis as a correlate of acquired immunity and clinical protection against P. falciparum malaria.
人体对疟原虫恶性疟原虫的天然体液免疫可以预防疾病，尽管确切的机制尚不清楚。虽然可以通过 ELISA 测量抗体水平，但很少有研究调查与临床结果相关的功能性抗体检测。在这项研究中，我们应用了一种最近开发的功能性抗体检测方法，检测在巴布亚新几内亚（PNG）疟疾流行地区进行的纵向队列研究中的血浆样本中的抗体介导的裂殖子调理作用。通过使用标准化和高通量方案的流式细胞术定量测定吞噬活性，并随后评估其与预防临床疟疾和高密度寄生虫血症的关联。发现调理抗体反应：i）随年龄增长而增加，ii）受到同时感染的增强，iii）与预防临床发作和高密度寄生虫血症相关。在基线时未检测到寄生虫血症的个体中观察到更强的保护相关性。这项研究首次证明裂殖体吞噬作用是获得性免疫和预防恶性疟原虫疟疾的临床保护的相关因素。
