Tian J H, Kumar S, Kaslow D C, Miller L H
Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Infect Immun. 1997 Aug;65(8):3032-6. doi: 10.1128/iai.65.8.3032-3036.1997.
Vaccination with native full-length merozoite surface protein 1 (MSP1) or with recombinant C-terminal peptides protects mice against lethal challenge with virulent malaria parasites. To determine whether other regions of MSP1 can also induce protection, Plasmodium yoelii MSP1 was divided into four separate regions. Each was expressed in Escherichia coli as a fusion protein with glutathione S-transferase (GST). The N-terminal fragment began after the cleavage site for the signal sequence and ended in the region comparable to the cleavage site for the C terminus of the 82-kDa peptide of Plasmodium falciparum. This expressed protein was 30 kDa smaller than the predicted peptide. One peptide from the middle region was produced, and the C terminus consisted of a 42-kDa fragment corresponding to the analogous peptide of P. falciparum and a 19-kDa fragment that extended 37 amino acids in the amino-terminal direction beyond the probable cleavage site. To test protection of mice against lethal P. yoelii challenge, three mouse strains (CAF1, BALB/c, and A/J) were vaccinated with each of the four recombinant proteins of MSP1. Mice vaccinated with the C-terminal 19-kDa protein were highly protected (described previously), as were those vaccinated with the 42-kDa protein that contained the 19-kDa fragment. The N-terminally expressed fragment of P. yoelii was not full length because of proteolytic cleavage in E. coli. The GST-82-kDa partial fragments induced some immunity, but the surviving mice still had high parasitemias. Vaccination with the peptide from the middle region of MSP1 gave minimal to no protection. Therefore, in addition to the C-terminal 19- and 42-kDa proteins, the only other fragment to give protection was the 82-kDa protein. The protection induced by the truncated 82-kDa protein was minimal compared with that of the C-terminal fragments.
用天然全长裂殖子表面蛋白1（MSP1）或重组C末端肽对小鼠进行疫苗接种可保护其免受恶性疟原虫的致命攻击。为了确定MSP1的其他区域是否也能诱导保护作用，约氏疟原虫MSP1被分为四个独立区域。每个区域都在大肠杆菌中作为与谷胱甘肽S-转移酶（GST）的融合蛋白表达。N末端片段从信号序列的切割位点之后开始，在与恶性疟原虫82 kDa肽C末端切割位点相当的区域结束。该表达的蛋白比预测的肽小30 kDa。产生了一个来自中间区域的肽，C末端由一个与恶性疟原虫类似肽相对应的42 kDa片段和一个在氨基末端方向超出可能切割位点延伸37个氨基酸的19 kDa片段组成。为了测试小鼠对约氏疟原虫致命攻击的保护作用，用MSP1的四种重组蛋白分别对三种小鼠品系（CAF1、BALB/c和A/J）进行疫苗接种。用C末端19 kDa蛋白接种的小鼠受到高度保护（如先前所述），用包含19 kDa片段的42 kDa蛋白接种的小鼠也是如此。由于在大肠杆菌中发生蛋白水解切割，约氏疟原虫N末端表达的片段不是全长的。GST-82 kDa部分片段诱导了一些免疫力，但存活的小鼠仍有高寄生虫血症。用MSP1中间区域的肽进行疫苗接种几乎没有或没有提供保护。因此，除了C末端19 kDa和42 kDa蛋白外，唯一能提供保护的其他片段是82 kDa蛋白。与C末端片段相比，截短的82 kDa蛋白诱导的保护作用最小。
