PLASMODIUM-FALCIPARUM - 2 ANTIGENS OF SIMILAR SIZE ARE LOCATED IN DIFFERENT COMPARTMENTS OF THE RHOPTRY
PLASMODIUM-FALCIPARUM - 2 ANTIGENS OF SIMILAR SIZE ARE LOCATED IN DIFFERENT COMPARTMENTS OF THE RHOPTRY
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DOI：
10.1016/0014-4894(90)90100-q
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发表时间：
1990-02-01
影响因子：
2.1
通讯作者：
ANDERS, RF
中科院分区：
文献类型：
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作者：
CREWTHER, PE;CULVENOR, JG;ANDERS, RF
两种先前描述的抗原，AMA-1和QF 3，它们位于恶性疟原虫裂殖子的棒状体中，具有相似相对分子质量的多肽。在免疫印迹中，两种抗原的抗体识别相对分子质量为80，000和62，000的所有分离株中的多肽。双向电泳结果表明，两种抗原的等电点不同，QF 3比AMA-1碱性更强。AMA-1可溶于Triton X-114，而QF 3在温度依赖性相分离后分配到水相中。在免疫电镜研究中，QF 3被发现在棒状体的身体，而AMA-1被一致地发现在棒状体的颈部。这两种抗原在成熟的裂殖子和裂殖子中通过荧光显微镜观察时都呈现点状双点模式，但AMA-1抗体也显示标记裂殖子表面。QF 3也在环感染的红细胞中检测到，而AMA-1则没有。 两种抗原的合成首先在成熟滋养体和未成熟滋养体中观察到。脉冲追踪实验表明，AMA-1基因的Mr 80，000多肽立即加工成Mr 62，000产物。这种切割模式不是阶段特异性的。QF 3的Mr 80，000多肽衍生自短寿命的Mr 84，000前体多肽。将Mr 80，000多肽加工成Mr 62，000多肽仅限于裂殖子成熟和再侵入的时期。因此，AMA-1和QF 3是不同的抗原，具有相似大小的多肽，但位于裂殖子棒状体的不同区室中。
Two previously described antigens, AMA-1 and QF3, which are located in the rhoptries of Plasmodium falciparum merozoites have polypeptides of similar relative molecular masses. On immunoblots, antibodies to both antigens recognized polypeptides of relative molecular mass 80,000 and 62,000 in all isolates tested. Two-dimensional electrophoresis showed that the isoelectric points of the two antigens were different, QF3 being more basic than AMA-1. AMA-1 was soluble in Triton X-114 whereas QF3 partitioned into the aqueous phase after temperature-dependent phase separation. In immunoelectron microscopic studies, QF3 was found in the body of the rhoptry whereas AMA-1 was consistently found in the neck of the rhoptry. Both antigens gave a punctate double-dot pattern in mature schizonts and merozoites when visualized by fluorescence microscopy, but AMA-1 antibodies also appeared to label the merozoite surface. QF3 wa also detected in ring-infected erythrocytes whereas AMA-1 was not. Synthesis of both antigens was first observed in mature trophozoites and immature schizonts. Pulse-chase experiments showed that the Mr 80,000 polypeptide of the AMA-1 gene was subject to immediate processing to the Mr 62,000 product. This cleavage pattern was not stage specific. The Mr 80,000 polypeptide of QF3 was derived from a short-lived Mr 84,000 precursor polypeptide. Processing of the Mr 80,000 polypeptide to an Mr 62,000 polypeptide was restricted to the period of merozoite maturation and reinvasion. Hence AMA-1 and QF3 are different antigens with polypeptides of similar size but located in different compartments of the merozoite rhoptries.