Mamuti Wulamu, Sako Yasuhito, Nakao Minoru, Xiao Ning, Nakaya Kazuhiro, Ishikawa Yuji, Yamasaki Hiroshi, Lightowlers Marshall W, Ito Akira
Department of Parasitology, Asahikawa Medical College, Japan.
Parasitol Int. 2006;55 Suppl:S57-62. doi: 10.1016/j.parint.2005.11.008. Epub 2005 Dec 19.
Antigen B (AgB) in hydatid cyst fluid of Echinococcus granulosus is a polymeric lipoprotein of 160 kDa and a highly immunogenic major antigen in echinococcal infection. The antigen is comprised of a group of subunit monomers of approximately 8 kDa in molecular size. Recent studies have revealed that the E. granulosus AgB (EgAgB) shows a high degree of genetic variability and the genes encoding the EgAgB 8-kDa subunit monomers that have been identified to date could be grouped into four clades, corresponding to the genes EgAgB8/1, EgAgB8/2, EgAgB8/3 and EgAgB8/4. It has been suggested that the recombinant EgAgB8/2 (rEgAgB8/2) provides better performance in serodiagnosis of human cystic echinococcosis (CE) than does the recombinant EgAgB8/1 (rEgAgB8/1). The EgAgB has been identified as a protease inhibitor with an ability to inhibit recruitment of neutrophils and exploit activation of T helper cells by eliciting a non-protective Th2 cell response, predominantly in patients with progressive CE. Recently it has been revealed that AgB also exists in the cyst fluid of Echinococcus multilocularis. Five different cDNAs encoding the EgAgB homologues have been identified in vesicles, protoscoleces and/or immature adult worms of E. multilocularis and named as EmAgB8/1, EmAgB8/2, EmAgB8/3, EmAgB8/4 and EmAgB8/5. These genes appeared to be expressed in a developmentally regulated manner in the parasite life cycle. This review focuses on recent advances in molecular biological and immunological characterization of AgB from both of E. granulosus and E. multilocularis.
细粒棘球绦虫包虫囊肿液中的抗原B（AgB）是一种160 kDa的聚合脂蛋白，是棘球绦虫感染中具有高度免疫原性的主要抗原。该抗原由一组分子大小约为8 kDa的亚基单体组成。最近的研究表明，细粒棘球绦虫AgB（EgAgB）表现出高度的遗传变异性，迄今为止已鉴定出的编码EgAgB 8 kDa亚基单体的基因可分为四个进化枝，分别对应于基因EgAgB8/1、EgAgB8/2、EgAgB8/3和EgAgB8/4。有人提出，重组EgAgB8/2（rEgAgB8/2）在人类囊型棘球蚴病（CE）的血清学诊断中比重组EgAgB8/1（rEgAgB8/1）表现更好。EgAgB已被鉴定为一种蛋白酶抑制剂，能够抑制中性粒细胞的募集，并通过引发非保护性的Th2细胞反应来利用T辅助细胞的激活，这在进行性CE患者中尤为明显。最近发现，AgB也存在于多房棘球绦虫的囊肿液中。在多房棘球绦虫的囊泡、原头节和/或未成熟成虫中已鉴定出五个编码EgAgB同源物的不同cDNA，并命名为EmAgB8/1、EmAgB8/2、EmAgB8/3、EmAgB8/4和EmAgB8/5。这些基因似乎在寄生虫生命周期中以发育调控的方式表达。本综述重点关注细粒棘球绦虫和多房棘球绦虫AgB在分子生物学和免疫学特征方面的最新进展。
