Teo Andrew, Hasang Wina, Randall Louise M, Feng Gaoqian, Bell Lauren, Unger Holger, Langer Christine, Beeson James G, Siba Peter M, Mueller Ivo, Molyneux Malcolm E, Brown Graham V, Rogerson Stephen J
Department of Medicine Doherty Institute.
Department of Medicine Victorian Infectious Diseases Service Doherty Institute.
J Infect Dis. 2014 Nov 1;210(9):1444-55. doi: 10.1093/infdis/jiu264. Epub 2014 May 5.
As malaria control is intensified, pregnant women may be less exposed to malaria, thus affecting the acquisition of protective antibody.
Plasma samples were collected from Malawian and Papua New Guinean (PNG) pregnant women enrolled over 7-year periods, during which malaria prevalence fell by over two thirds. Immunoglobulin G (IgG) levels to schizont extract, merozoite antigens, and VAR2CSA-DBL5ε were measured by enzyme-linked immunosorbent assay (ELISA). Levels of IgG to variant surface antigens of infected erythrocytes (IEs) and merozoites and levels of opsonizing IgG to IEs were measured by flow cytometry.
In both settings, levels of antibodies in pregnant women to recombinant antigens and to intact IEs but not of opsonizing antibodies decreased over time. After adjustment for coverage with insecticide-treated bed nets (ITNs), these differences disappeared in the Malawian cohort, whereas in the PNG cohort, time was independently associated with a decrease in several antibody responses measured by ELISA.
The impact of falling parasite prevalence on anti-Plasmodium falciparum serological indicators in pregnant women varies by setting. Increased ITN coverage may affect development of antibodies to recombinant antigens, but levels of opsonizing IgG remained stable over time. Opsonizing IgG against placental-binding IEs may persist, thus offering longer-lasting protection against malaria during pregnancy.
随着疟疾防控力度加大，孕妇接触疟疾的机会可能减少，从而影响保护性抗体的获得。
收集了在7年期间入组的马拉维和巴布亚新几内亚（PNG）孕妇的血浆样本，在此期间疟疾流行率下降了三分之二以上。通过酶联免疫吸附测定（ELISA）测量针对裂殖体提取物、裂殖子抗原和VAR2CSA-DBL5ε的免疫球蛋白G（IgG）水平。通过流式细胞术测量针对感染红细胞（IEs）和裂殖子的变异表面抗原的IgG水平以及针对IEs的调理IgG水平。
在这两种情况下，孕妇针对重组抗原和完整IEs的抗体水平随时间下降，但调理抗体水平未下降。在调整了经杀虫剂处理的蚊帐（ITNs）的覆盖率后，这些差异在马拉维队列中消失，而在巴布亚新几内亚队列中，时间与ELISA测量的几种抗体反应的下降独立相关。
寄生虫流行率下降对孕妇抗恶性疟原虫血清学指标的影响因地区而异。ITN覆盖率的增加可能会影响针对重组抗原的抗体的产生，但调理IgG水平随时间保持稳定。针对胎盘结合性IEs的调理IgG可能会持续存在，从而在孕期提供更持久的疟疾保护。
