Limits...
Inconsistent protective efficacy and marked polymorphism limits the value of Schistosoma japonicum tetraspanin-2 as a vaccine target.

Zhang W, Li J, Duke M, Jones MK, Kuang L, Zhang J, Blair D, Li Y, McManus DP - PLoS Negl Trop Dis (2011)

Bottom Line: We determined the protective efficacy of one subclass - Sj-TSP-2e.Following the alignment of 211 cDNAs, we identified 7 clusters encoding S. japonicum TSP-2 (Sj-TSP-2) based on sequence variation in the large extracellular loop (LEL) region with differing frequency of transcription in male and female worms.We expressed in E. coli the LEL region of one of the clusters which exhibited a high frequency of transcription in female worms, and showed the purified recombinant protein (Sj-TSP-2e) was recognised by 43.1% of sera obtained from confirmed schistosomiasis japonica patients.

View Article: PubMed Central - PubMed

Affiliation: Molecular Parasitology Laboratory, Australian Centre for International and Tropical Health and Nutrition, Queensland Institute of Medical Research, Brisbane, Queensland, Australia.

ABSTRACT

Background: Schistosoma mansoni tetraspanin 2 (Sm-TSP-2) has been shown to be strongly recognized by IgG1 and IgG3 antibodies from individuals putatively resistant to schistosome infection, but not chronically infected people, and to induce high levels of protection against challenge infection in the murine model of schistosomiasis. Amplification by PCR of homologous sequences from male and female S. japonicum worms showed the presence of 7 different clusters or subclasses of S. japonicum TSP-2. We determined the protective efficacy of one subclass - Sj-TSP-2e.

Methodology/principal findings: Following the alignment of 211 cDNAs, we identified 7 clusters encoding S. japonicum TSP-2 (Sj-TSP-2) based on sequence variation in the large extracellular loop (LEL) region with differing frequency of transcription in male and female worms. Quantitative PCR analysis revealed elevated expression of Sj-TSP-2 in adult worms compared with other life cycle stages. We expressed in E. coli the LEL region of one of the clusters which exhibited a high frequency of transcription in female worms, and showed the purified recombinant protein (Sj-TSP-2e) was recognised by 43.1% of sera obtained from confirmed schistosomiasis japonica patients. Vaccination of mice with the recombinant protein induced high levels of IgG1 and IgG2 antibodies, but no consistent protective efficacy against challenge infection was elicited in three independent trials.

Conclusions/significance: The highly polymorphic nature of the Sj-TSP-2 gene at the transcriptional level may limit the value of Sj-TSP-2 as a target for future S. japonicum vaccine development.

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Related in: MedlinePlus

Expression levels of Sj-TSP-2e by real-time PCR.cDNAs were amplified with mRNA isolated from different stages of S. japonicum using specific primers designed from the conserved regions of Sj-TSP-2e. Ce, cercariae; So, schistosomula; Pw, paired adult worms; Ma, males; Fe, females. The bars (and *, X axis) show the fold changes compared with the cercarial stage. We used NADH-ubiquinone reductase as a house-keeping gene to calculate the number of copies of the gene expressed in each of the stages, and then converted these to fold changes by comparison with the number of copies in cercariae.
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pntd-0001166-g003: Expression levels of Sj-TSP-2e by real-time PCR.cDNAs were amplified with mRNA isolated from different stages of S. japonicum using specific primers designed from the conserved regions of Sj-TSP-2e. Ce, cercariae; So, schistosomula; Pw, paired adult worms; Ma, males; Fe, females. The bars (and *, X axis) show the fold changes compared with the cercarial stage. We used NADH-ubiquinone reductase as a house-keeping gene to calculate the number of copies of the gene expressed in each of the stages, and then converted these to fold changes by comparison with the number of copies in cercariae.

Mentions: We used real time PCR to quantify the expression levels of Sj-TSP-2 in different stages of S. japonicum with a pair of primers designed from the identical regions of the clusters. The analysis showed that Sj-TSP-2 was differentially transcribed in different stages of the parasite, with the gene being expressed 6 and 30 times higher in schistosomula and adult worms, respectively, than in cercariae. In addition, expression of Sj-TSP-2 was 47-fold higher in adult males and 8.7 times higher in adult females compared with the cercariae (Fig. 3).


Inconsistent protective efficacy and marked polymorphism limits the value of Schistosoma japonicum tetraspanin-2 as a vaccine target.

Zhang W, Li J, Duke M, Jones MK, Kuang L, Zhang J, Blair D, Li Y, McManus DP - PLoS Negl Trop Dis (2011)

Expression levels of Sj-TSP-2e by real-time PCR.cDNAs were amplified with mRNA isolated from different stages of S. japonicum using specific primers designed from the conserved regions of Sj-TSP-2e. Ce, cercariae; So, schistosomula; Pw, paired adult worms; Ma, males; Fe, females. The bars (and *, X axis) show the fold changes compared with the cercarial stage. We used NADH-ubiquinone reductase as a house-keeping gene to calculate the number of copies of the gene expressed in each of the stages, and then converted these to fold changes by comparison with the number of copies in cercariae.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3104969&req=5

pntd-0001166-g003: Expression levels of Sj-TSP-2e by real-time PCR.cDNAs were amplified with mRNA isolated from different stages of S. japonicum using specific primers designed from the conserved regions of Sj-TSP-2e. Ce, cercariae; So, schistosomula; Pw, paired adult worms; Ma, males; Fe, females. The bars (and *, X axis) show the fold changes compared with the cercarial stage. We used NADH-ubiquinone reductase as a house-keeping gene to calculate the number of copies of the gene expressed in each of the stages, and then converted these to fold changes by comparison with the number of copies in cercariae.
Mentions: We used real time PCR to quantify the expression levels of Sj-TSP-2 in different stages of S. japonicum with a pair of primers designed from the identical regions of the clusters. The analysis showed that Sj-TSP-2 was differentially transcribed in different stages of the parasite, with the gene being expressed 6 and 30 times higher in schistosomula and adult worms, respectively, than in cercariae. In addition, expression of Sj-TSP-2 was 47-fold higher in adult males and 8.7 times higher in adult females compared with the cercariae (Fig. 3).

Bottom Line: We determined the protective efficacy of one subclass - Sj-TSP-2e.Following the alignment of 211 cDNAs, we identified 7 clusters encoding S. japonicum TSP-2 (Sj-TSP-2) based on sequence variation in the large extracellular loop (LEL) region with differing frequency of transcription in male and female worms.We expressed in E. coli the LEL region of one of the clusters which exhibited a high frequency of transcription in female worms, and showed the purified recombinant protein (Sj-TSP-2e) was recognised by 43.1% of sera obtained from confirmed schistosomiasis japonica patients.

View Article: PubMed Central - PubMed

Affiliation: Molecular Parasitology Laboratory, Australian Centre for International and Tropical Health and Nutrition, Queensland Institute of Medical Research, Brisbane, Queensland, Australia.

ABSTRACT

Background: Schistosoma mansoni tetraspanin 2 (Sm-TSP-2) has been shown to be strongly recognized by IgG1 and IgG3 antibodies from individuals putatively resistant to schistosome infection, but not chronically infected people, and to induce high levels of protection against challenge infection in the murine model of schistosomiasis. Amplification by PCR of homologous sequences from male and female S. japonicum worms showed the presence of 7 different clusters or subclasses of S. japonicum TSP-2. We determined the protective efficacy of one subclass - Sj-TSP-2e.

Methodology/principal findings: Following the alignment of 211 cDNAs, we identified 7 clusters encoding S. japonicum TSP-2 (Sj-TSP-2) based on sequence variation in the large extracellular loop (LEL) region with differing frequency of transcription in male and female worms. Quantitative PCR analysis revealed elevated expression of Sj-TSP-2 in adult worms compared with other life cycle stages. We expressed in E. coli the LEL region of one of the clusters which exhibited a high frequency of transcription in female worms, and showed the purified recombinant protein (Sj-TSP-2e) was recognised by 43.1% of sera obtained from confirmed schistosomiasis japonica patients. Vaccination of mice with the recombinant protein induced high levels of IgG1 and IgG2 antibodies, but no consistent protective efficacy against challenge infection was elicited in three independent trials.

Conclusions/significance: The highly polymorphic nature of the Sj-TSP-2 gene at the transcriptional level may limit the value of Sj-TSP-2 as a target for future S. japonicum vaccine development.

Show MeSH
Related in: MedlinePlus