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首页> 外文期刊>Infection and immunity >Inhibition of malaria parasite invasion of human erythrocytes by a lymphocyte membrane polypeptide.
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Inhibition of malaria parasite invasion of human erythrocytes by a lymphocyte membrane polypeptide.

机译：淋巴细胞膜多肽抑制疟原虫入侵人红细胞。

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Extraction by boiling of the buffy coat of human blood yields a protein solution which inhibits the propagation of the human malaria parasite Plasmodium falciparum in culture with a 50% inhibitory dose of 105 micrograms of protein per ml. The inhibitory activity is associated exclusively with the lymphocytes and affects solely the invasion of erythrocytes by free merozoites. Boiled extracts of isolated lymphocytes had a 50% inhibitory dose of 22 micrograms/ml. Fractionation of surface-labeled or pronase-treated lymphocytes revealed that the antimalarial lymphocyte factor is associated with the intracellular aspect of the membrane fraction and is probably not involved in the host defense system against malaria. Further purification by salt extraction, ion-exchange chromatography, molecular gel filtration, and electroelution from lithium dodecyl sulfate-polyacrylamide gels resulted in 300- to 550-fold purification, i.e., a 50% inhibitory dose of 40 to 70 ng/ml. All inhibitory fractions contained a 48-kilodalton polypeptide which eluted from a gel filtration column as a 400-kilodalton species, implying multimeric association. Some 6,000 molecules of the 48-kilodalton polypeptide bind with high affinity to one merozoite, the free form of the parasite. The Kd of 0.1 to 0.5 nM for the binding of the 48-kilodalton polypeptide correlated well with the 50% inhibitory dose of 0.3 to 0.4 nM obtained with purified active antimalarial lymphocyte factor. We therefore suggest that the 48-kilodalton polypeptide partially purified from lymphocyte membranes is the antimalarial lymphocyte factor and that it exerts its inhibitory activity by binding to merozoites, thereby preventing their invasion into erythrocytes. The antimalarial lymphocyte factor or a polypeptide sequence thereof could serve for further probing of invasion at the molecular level.
机译：通过沸腾人血的血沉棕黄层提取而得到的蛋白质溶液抑制了人类疟疾寄生虫恶性疟原虫在培养物中的传播，其抑制率为50％，每毫升蛋白质为105微克蛋白质。抑制活性仅与淋巴细胞有关，并且仅影响游离裂殖子对红细胞的入侵。煮沸的分离的淋巴细胞提取物的50％抑制剂量为22微克/毫升。表面标记的或经蛋白酶处理的淋巴细胞的分离显示抗疟疾淋巴细胞因子与膜组分的细胞内有关，并且可能不参与抗疟疾的宿主防御系统。通过盐提取，离子交换色谱，分子凝胶过滤和十二烷基硫酸锂-聚丙烯酰胺凝胶的电洗脱进一步纯化导致300到550倍纯化，即50％抑制剂量为40至70 ng / ml。所有抑制性级分均含有48千达尔顿多肽，该多肽从凝胶过滤柱中洗脱为400千达多肽种类，这意味着多聚体缔合。大约6,000个48-千达尔顿多肽分子与一种裂殖子（寄生虫的游离形式）高亲和力结合。结合48-千洛酮多肽的Kd为0.1至0.5 nM，与纯化的活性抗疟疾淋巴细胞因子获得的50％抑制剂量0.3至0.4 nM密切相关。因此，我们建议从淋巴细胞膜部分纯化的48-千洛酮多肽是抗疟疾淋巴细胞因子，并且它通过与裂殖子结合而发挥其抑制活性，从而防止它们侵入红细胞。抗疟疾淋巴细胞因子或其多肽序列可用于在分子水平上进一步探测侵袭。

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