Metzger Wolfram G, Okenu Daniel M N, Cavanagh David R, Robinson Jane V, Bojang Kalifa A, Weiss Helen A, McBride Jana S, Greenwood Brian M, Conway David J
Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
Parasite Immunol. 2003 Jun;25(6):307-12. doi: 10.1046/j.1365-3024.2003.00636.x.
The merozoite surface protein 2 (MSP2) of Plasmodium falciparum is recognized by human antibodies elicited during natural infections, and may be a target of protective immunity. In this prospective study, serum IgG antibodies to MSP2 were determined in a cohort of 329 Gambian children immediately before the annual malaria transmission season, and the incidence of clinical malaria in the following 5 months was monitored. Three recombinant MSP2 antigens were used, representing each of the two major allelic serogroups and a conserved region. The prevalence of serum IgG to each antigen correlated positively with age and with the presence of parasitaemia at the time of sampling. These antibodies were associated with a reduced subsequent incidence of clinical malaria during the follow-up. This trend was seen for both IgG1 and IgG3, although the statistical significance was greater for IgG3, the most common subclass against MSP2. After adjusting for potentially confounding effects of age and pre-season parasitaemia, IgG3 reactivities against each of the major serogroups of MSP2 remained significantly associated with a lower prospective risk of clinical malaria. Individuals who had IgG3 reactivity to both of the MSP2 serogroup antigens had an even more significantly reduced risk. Importantly, this effect remained significant after adjusting for a simultaneous strong protective association of antibodies to another antigen (MSP1 block 2) which itself remained highly significant.
恶性疟原虫的裂殖子表面蛋白2（MSP2）可被自然感染期间产生的人体抗体识别，可能是保护性免疫的靶点。在这项前瞻性研究中，在329名冈比亚儿童年度疟疾传播季节开始前即刻测定了其血清中针对MSP2的IgG抗体，并监测了随后5个月内临床疟疾的发病率。使用了三种重组MSP2抗原，分别代表两个主要等位基因血清群和一个保守区域。血清中针对每种抗原的IgG流行率与年龄以及采样时的寄生虫血症呈正相关。这些抗体与随访期间临床疟疾随后发病率的降低有关。IgG1和IgG3均呈现出这种趋势，尽管IgG3（针对MSP2最常见的亚类）的统计学意义更大。在调整年龄和季节前寄生虫血症的潜在混杂效应后，针对MSP2各主要血清群的IgG3反应性仍与临床疟疾较低的前瞻性风险显著相关。对MSP2血清群两种抗原均有IgG3反应性的个体，其风险降低更为显著。重要的是，在调整了针对另一种抗原（MSP1第2区）的抗体同时存在的强烈保护关联后（该关联本身仍高度显著），这种效应仍然显著。
