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Cloning and characterization of a Schistosoma mansoni cDNA clone with a specific antigenic expression during
A M Coelho-Castelo1, V Rodrigues
1Departamento de Parasitologia, Microbiologia e Imunologia, Faculdade de Medicina de Ribeirão Preto, USP, Brasil. vrodrigu@famrp.usp.br
Abstract:
Approximately 2.0 x 10 cDNA clones of an Schistosoma mansoni lambda gt11 cDNA library were screened in duplicate with serum from infected mice corresponding to distinct phases of infection. A cDNA clone (7/1) was isolated and recognized only by seven week serum. The clone was subcloned in pGEX-2T and Western-blot studies showed a specific antigenic expression confirming that only serum from the chronic phase is capable of recognizing this antigen. Dot-hybridization with RNA from different developmental phases of the parasite showed that the corresponding 7/1 RNA is expressed in all phases of parasite development in vertebrate hosts.
Insights
Researchers identified a specific Schistosoma mansoni antigen (7/1 clone) recognized only during the chronic infection phase. This Schistosoma mansoni antigen is expressed throughout all parasite developmental stages in vertebrate hosts.
Area of Science:
- Parasitology
- Immunology
- Molecular Biology
Background:
- Schistosoma mansoni is a parasitic flatworm causing schistosomiasis, a significant human health concern.
- Understanding parasite antigens is crucial for developing diagnostic tools and effective treatments.
- Identifying stage-specific antigens can provide insights into host-parasite interactions.
Purpose of the Study:
- To isolate and characterize Schistosoma mansoni cDNA clones recognized by immune sera from infected hosts.
- To determine the developmental expression profile of a specific Schistosoma mansoni antigen.
- To identify potential diagnostic or therapeutic targets for schistosomiasis.
Main Methods:
- Screening of a Schistosoma mansoni lambda gt11 cDNA library with serum from infected mice.
- Subcloning of a reactive cDNA clone (7/1) into pGEX-2T for expression.
- Western blot analysis to confirm antigenic expression and recognition by specific immune sera.
- Dot-hybridization to assess RNA expression across different parasite developmental stages.
Main Results:
- A cDNA clone, designated 7/1, was isolated and specifically recognized by serum from mice in the chronic infection phase (seven weeks).
- Western blot confirmed that the 7/1 clone expresses a specific antigen recognized exclusively by chronic phase serum.
- Dot-hybridization revealed that the RNA corresponding to the 7/1 clone is expressed throughout all developmental phases of Schistosoma mansoni within the vertebrate host.
Conclusions:
- The 7/1 clone represents a Schistosoma mansoni antigen predominantly recognized during the chronic phase of infection.
- Despite late-phase recognition, the antigen's RNA is constitutively expressed across all parasite developmental stages.
- This antigen may serve as a valuable marker for chronic schistosomiasis or a target for immunomodulation.