Genetic diversity and phylogenetic analysis of EG95 sequences of Echinococcus granulosus: Implications for EG95 vaccine application
10.1016/j.apjtm.2017.05.011
- Author:
Wei PAN
1
;
De-Sheng CHEN
1
;
Yun-Juan LU
1
;
Hui-Wen XU
1
;
Wen-Ting HAO
1
;
Ya-Wen ZHANG
1
;
Su-Ping QIN
1
;
Kui-Yang ZHENG
1
;
Ren-Xian TANG
1
;
De-Sheng CHEN
2
;
Yun-Juan LU
2
;
Hui-Wen XU
2
;
Ya-Wen ZHANG
2
Author Information
1. Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Laboratory of Infection and Immunity, Xuzhou Medical University
2. Department of Clinical Medicine, Xuzhou Medical University
- Publication Type:Journal Article
- Keywords:
Cystic echinococcosis;
Echinococcus granulosus;
EG95;
Genetic diversity;
Vaccine
- From:
Asian Pacific Journal of Tropical Medicine
2017;10(5):524-527
- CountryChina
- Language:Chinese
-
Abstract:
Objective To analyse the genetic variability of EG95 sequences and provide guidance for EG95 vaccine application against Echinococcus granulosus (E. granulosus). Methods We analysed EG95 polymorphism by collecting total 97 different E. granulosus isolates from 12 different host species that originated from 10 different countries. Multiple sequence alignments and the homology were performed by Lasergene 1 (DNASTAR Inc., Madison, WI), and the phylogenetic analysis was performed by using MEGA5.1 (CEMI, Tempe, AZ, USA). In addition, linear and conformational epitopes were analysed, including secondary structure, NXT/S glycosylation, fibronectin type III (FnIII) domain and glycosylphosphatidylinositol anchor signal (GPI-anchor). The secondary structure was predicted by PSIPRED method. Results Our results indicated that most isolates overall shared 72.6–100% identity in EG95 gene sequence with the published standard EG95 sequence, X90928. However, EG95 gene indeed has polymorphism in different isolates. Phylogenetic analysis showed that different isolates could be divided into three subgroups. Subgroup 1 contained 87 isolates while Subgroup 2 and Subgroup 3 consisted of 3 and 7 isolates, respectively. Four sequences cloned from oncosphere shared a high identity with the parental sequence of the current vaccine, X90928, and they belonged to Subgroup 1. However, in comparison to X90928, several amino acid mutations occurred in most isolates besides oncosphere, which potentially altered the immunodominant linear epitopes, glycosylation sites and secondary structures in EG95 genes. All these variations might change their previous antigenicity and thereby affecting the efficacy of current EG95 vaccine. Conclusions This study reveals the genetic variability of EG95 sequences in different E. granulosus isolates, and proposed that more vaccination trials would be needed to test the effectiveness of current EG95 vaccine against distinct isolates in different countries.
