Freeman R R, Holder A A
J Exp Med. 1983 Nov 1;158(5):1647-53. doi: 10.1084/jem.158.5.1647.
A technique was developed for obtaining high yields of naturally released Plasmodium falciparum merozoites from synchronous cultures of parasitized erythrocytes. The cultured erythrocytes were treated with trypsin to prevent reinvasion (6), and the released merozoites that accumulated extracellularly were harvested by differential centrifugation. The total biosynthetically labeled proteins of schizonts and merozoites, and those immunoprecipitated by human immune serum were analyzed and compared. The surface antigens of free merozoites, labeled by lactoperoxidase-catalyzed iodination, were also described. A monoclonal antibody, specific for a 195,000 mol wt schizont protein, and processing fragments derived from it (3) were used in immunoprecipitation and Western transfer analyses to determine which of the processing fragments are associated with merozoites and which of them are located on the merozoite surface. It was found that processing of the 195,000 mol wt precursor down to an 83,000 mol wt fragment is complete in free merozoites, and that this fragment is expressed as one of the major surface antigens of P. falciparum merozoites.
已开发出一种从受疟原虫寄生的红细胞同步培养物中获得高产率自然释放的恶性疟原虫裂殖子的技术。用胰蛋白酶处理培养的红细胞以防止再次入侵（6），通过差速离心收集细胞外积累的释放裂殖子。对裂殖体和裂殖子的总生物合成标记蛋白以及人免疫血清免疫沉淀的蛋白进行分析和比较。还描述了通过乳过氧化物酶催化碘化标记的游离裂殖子的表面抗原。使用针对195,000摩尔质量裂殖体蛋白及其衍生加工片段的单克隆抗体（3）进行免疫沉淀和Western印迹分析，以确定哪些加工片段与裂殖子相关以及哪些位于裂殖子表面。发现游离裂殖子中195,000摩尔质量前体加工成83,000摩尔质量片段的过程是完整的，并且该片段作为恶性疟原虫裂殖子的主要表面抗原之一表达。
