A protective glycosylphosphatidylinositol-anchored membrane protein of Plasmodium yoelii trophozoites and merozoites contains two epidermal growth factor-like domains

被引:31
作者
Burns, JM [1 ]
Belk, CC [1 ]
Dunn, PD [1 ]
机构
[1] Meharry Med Coll, Dept Microbiol, Nashville, TN 37208 USA
关键词
D O I
10.1128/IAI.68.11.6189-6195.2000
中图分类号
R392 [医学免疫学]; Q939.91 [免疫学];
学科分类号
100102 ;
摘要
Using sera from mice immunized and protected against Plasmodium yoelii malaria, we identified a novel blood-stage antigen gene, pypag-2. The 2.1-kb pypag-2 cDNA contains a single open reading frame that encodes a 409-amino-acid protein with a predicted molecular mass of 46.8 kDa. Unlike many characterized plasmodial antigens, blocks of tandemly repeated amino acids are lacking in the pypAg-2 protein sequence. Recombinant pypAg-2, comprising the full-length protein minus the predicted N-terminal signal and C-terminal anchor sequences, was produced and used to raise a high-titer polyclonal rabbit antiserum. This antiserum was used to identify and characterize the native protein through immunoblotting, immunoprecipitation and immunofluorescence assays. Consistent with the presence of a glycosylphosphatidylinositol anchor, pypAg-2 fractionated with the detergent phase of Triton X-114-solubilized proteins and could be metabolically labeled with [H-3]palmitic acid. By immunofluorescence, pypAg-2 expression was localized to both the trophozoite and merozoite membranes. Similar to Plasmodium falciparum merozoite surface protein 1, pypAg-2 contains two C-terminal epidermal growth factor (EGF)-like domains. Most importantly, immunization with recombinant pypAg-2 protected mice against lethal P. yoelii malaria. Thus, pypAg-2 is a target of protective immune responses and represents a novel addition to the family of merozoite surface proteins that contain one or more EGF-like domains.
引用
收藏
页码:6189 / 6195
页数:7
相关论文
共 46 条