Temporal variation of the merozoite surface protein-2 gene of Plasmodium falciparum
Temporal variation of the merozoite surface protein-2 gene of Plasmodium falciparum
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DOI：
10.1128/iai.66.1.239-246.1998
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发表时间：
1998-01-01
影响因子：
3.1
通讯作者：
Coppel, RL
中科院分区：
文献类型：
--
作者：
Eisen, D;Billman-Jacobe, H;Coppel, RL
关键寄生虫抗原的广泛多态性可能会妨碍亚单位疫苗对抗恶性疟原虫感染的有效性。然而，人们对疟疾流行的不同地区自然传播的菌株的抗原库范围知之甚少。为了解决这个问题，我们进行了一项研究，从生活在伊里安查亚西部一个小村庄内的寄生虫个体中采集血液样本，并使用引物进行 PCR 扩增，从而可以扩增编码裂殖子表面蛋白 2 (MSP2) 的基因。我们确定了扩增产物的核苷酸序列，并将推导的氨基酸序列与从 29 个月前在同一村庄收集的样品中获得的序列进行了比较。在两个时间点均观察到属于两个主要等位基因家族的 MSP2 基因。以 FC27 MSP2 家族为例，我们观察到大多数个体都被表达相同形式 MSP2 的寄生虫感染。表达 3D7 MSP2 家族等位基因的寄生虫感染更具异质性。无论是对于整个群体还是对于在两个时间点进行检测的个体，在较早时间点观察到的 MSP2 等位基因在较晚时间点均未检测到。我们使用两次主要调查之间采集的血液样本对一部分感染患者进行了检查。我们无法在任何患者中检测到表达先前遇到的 MSP2 形式的寄生虫的再感染。我们的结果与感染诱导针对 MSP2 抗原的一种菌株特异性免疫反应的可能性一致，该免疫反应偏向于防止带有相同形式 MSP2 的寄生虫的再感染。
Extensive polymorphism of key parasite antigens is likely to hamper the effectiveness of subunit vaccines against Plasmodium falciparum infection. However, little is known about the extent of the antigenic repertoire of naturally circulating strains in different areas where malaria is endemic. To address this question,,ve conducted a study in which blood samples were collected from parasitemic individuals living within a small hamlet in Western Irian Jaya and Subjected to PCR amplification using primers that would allow amplification of the gene encoding merozoite surface protein-2 (MSP2). We determined the nucleotide sequence of the amplified product and compared the deduced amino acid sequences to sequences obtained from samples collected in the same hamlet 29 months previously. MSP2 genes belonging to both major allelic families were observed at both time points. In the Case of the FC27 MSP2 family, we observed that the majority of individuals were infected by parasites expressing the same form of MSP2. Infections with parasites expressing 3D7 MSP2 family alleles were more heterogeneous. No MSP2 alleles observed at the earlier time point were detectable at the later time point, either for the population as a whole or for individuals who were assayed at both time points. We examined a subset of the infected patients by using blood samples taken between the two major surveys. In no patients could we detect reinfection by a parasite expressing a previously encountered form of MSP2. Our results are consistent with the possibility that infection induces a form of strain-specific immune response against the MSP2 antigen that biases against reinfection by parasites bearing identical forms of MSP2.