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

Antibody isotype levels in mice challenged with 35 S. japonicum cercariae.Mouse serum anti-Sj-TSP-2e (fused with thioredoxin, Thi) antibodies were determined by ELISA after primary vaccination with S. japonicum-TSP-2e (Sj-TSP-2e) or S. mansoni-TSP-2 (Sm-TSP-2). Thioredoxin was used as control protein in the vaccine trials. The thin arrows indicate vaccination time points and the bold arrows indicate the time point of cercarial challenge.
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pntd-0001166-g007: Antibody isotype levels in mice challenged with 35 S. japonicum cercariae.Mouse serum anti-Sj-TSP-2e (fused with thioredoxin, Thi) antibodies were determined by ELISA after primary vaccination with S. japonicum-TSP-2e (Sj-TSP-2e) or S. mansoni-TSP-2 (Sm-TSP-2). Thioredoxin was used as control protein in the vaccine trials. The thin arrows indicate vaccination time points and the bold arrows indicate the time point of cercarial challenge.

Mentions: In order to determine whether Sj-TSP-2e had any protective efficacy, three trials were undertaken; these comprised two experiments where mice were challenged with a high dose of 35 cercariae, and one experiment where mice were challenged with a low dose of 12 cercariae. Murine serum samples collected throughout the course of the vaccine trials with Sj-TSP-2e did not react in ELISA with thioredoxin fused with 6His alone (data not shown), indicating the very poor antigenicity of this tag protein. In contrast, the vaccinated mice generated high levels of IgG against SjT-SP-2e after the second injection and these peaked after the third injection; the serum titres dropped slightly just prior to perfusion of the mice (Fig. 7). Of the IgG subclasses, IgG1 antibodies were dominant and IgG2a antibodies were also increased significantly (Fig. 7). IgA, IgE and IgM were at background levels throughout the three trials (Fig. 7). IgG antibodies, including IgG1 and IgG2, in the sera collected from mice vaccinated with Sm-TSP-2 recognized Sj-TSP-2e (Fig. 7), indicating that the two antigens may share similar epitopes.


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)

Antibody isotype levels in mice challenged with 35 S. japonicum cercariae.Mouse serum anti-Sj-TSP-2e (fused with thioredoxin, Thi) antibodies were determined by ELISA after primary vaccination with S. japonicum-TSP-2e (Sj-TSP-2e) or S. mansoni-TSP-2 (Sm-TSP-2). Thioredoxin was used as control protein in the vaccine trials. The thin arrows indicate vaccination time points and the bold arrows indicate the time point of cercarial challenge.
© Copyright Policy
Related In: Results  -  Collection

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

pntd-0001166-g007: Antibody isotype levels in mice challenged with 35 S. japonicum cercariae.Mouse serum anti-Sj-TSP-2e (fused with thioredoxin, Thi) antibodies were determined by ELISA after primary vaccination with S. japonicum-TSP-2e (Sj-TSP-2e) or S. mansoni-TSP-2 (Sm-TSP-2). Thioredoxin was used as control protein in the vaccine trials. The thin arrows indicate vaccination time points and the bold arrows indicate the time point of cercarial challenge.
Mentions: In order to determine whether Sj-TSP-2e had any protective efficacy, three trials were undertaken; these comprised two experiments where mice were challenged with a high dose of 35 cercariae, and one experiment where mice were challenged with a low dose of 12 cercariae. Murine serum samples collected throughout the course of the vaccine trials with Sj-TSP-2e did not react in ELISA with thioredoxin fused with 6His alone (data not shown), indicating the very poor antigenicity of this tag protein. In contrast, the vaccinated mice generated high levels of IgG against SjT-SP-2e after the second injection and these peaked after the third injection; the serum titres dropped slightly just prior to perfusion of the mice (Fig. 7). Of the IgG subclasses, IgG1 antibodies were dominant and IgG2a antibodies were also increased significantly (Fig. 7). IgA, IgE and IgM were at background levels throughout the three trials (Fig. 7). IgG antibodies, including IgG1 and IgG2, in the sera collected from mice vaccinated with Sm-TSP-2 recognized Sj-TSP-2e (Fig. 7), indicating that the two antigens may share similar epitopes.

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