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New approaches with different types of circulating cathodic antigen for the diagnosis of patients with low Schistosoma mansoni load.

Grenfell R, Harn DA, Tundup S, Da'dara A, Siqueira L, Coelho PM - PLoS Negl Trop Dis (2013)

Bottom Line: In our previous investigations, the use of crude antigens led to false-positive results.Recently, focus has been given to highly purified Schistosoma mansoni antigens, especially to circulating antigens.Interestingly, the "crude antigen" worked as a good marker for control of cure after praziquantel treatment.

View Article: PubMed Central - PubMed

Affiliation: Schistosomiasis Laboratory, Rene Rachou Research Center, Oswaldo Cruz Foundation (Fiocruz), Belo Horizonte, Minas Gerais, Brazil.

ABSTRACT

Background: Schistosomiasis mansoni is a debilitating and sometimes fatal disease. Accurate diagnosis plays a key role in patient management and infection control. However, currently available parasitological methods are laborious and lack sensitivity. The selection of target antigen candidates has turned out to be a promising tool for the development of more sensitive diagnostic methods. In our previous investigations, the use of crude antigens led to false-positive results. Recently, focus has been given to highly purified Schistosoma mansoni antigens, especially to circulating antigens.

Method: Thus, our main goal was to test different types of circulating cathodic antigen glycoprotein (CCA), as "crude antigen," the protein chain of recombinant CCA and two individual peptides. These schistosome proteins/peptides were tested in a new diagnostic method employing immunomagnetic separation based on the improvement of antigen-antibody binding.

Principal findings: Use of recombinant CCA as a diagnostic antigen allowed us to develop a diagnostic assay with high sensitivity and specificity with no false-negative results. Interestingly, the "crude antigen" worked as a good marker for control of cure after praziquantel treatment.

Conclusions/significance: Our new diagnostic method was superior to enzyme-linked immunosorbent assay in diagnosing low endemicity patients.

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Related in: MedlinePlus

SDS-PAGE analysis of the “crude antigen” and the protein chain of recombinant CCA.Aliquots of samples corresponding to the final product of adult worm extract submitted to purification steps (2) and, the CCA recombinant protein expressed in E. coli before (3) and after (4) induction with IPTG were subjected to silver stained SDS-PAGE analysis. Electrophoresis was done using 12% Tris-glycine gels. Molecular weight standards are shown in (1).
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pntd-0002054-g001: SDS-PAGE analysis of the “crude antigen” and the protein chain of recombinant CCA.Aliquots of samples corresponding to the final product of adult worm extract submitted to purification steps (2) and, the CCA recombinant protein expressed in E. coli before (3) and after (4) induction with IPTG were subjected to silver stained SDS-PAGE analysis. Electrophoresis was done using 12% Tris-glycine gels. Molecular weight standards are shown in (1).

Mentions: Four different forms of CCA were obtained and tested in IMS assays. Initially, the “crude antigen” was obtained from adult worm extracts and the CCAr were induced in E. coli. Final products are shown on Figure 1 and both demonstrated a 30 kDa protein, correlating with previously reported characteristics of CCA [25].


New approaches with different types of circulating cathodic antigen for the diagnosis of patients with low Schistosoma mansoni load.

Grenfell R, Harn DA, Tundup S, Da'dara A, Siqueira L, Coelho PM - PLoS Negl Trop Dis (2013)

SDS-PAGE analysis of the “crude antigen” and the protein chain of recombinant CCA.Aliquots of samples corresponding to the final product of adult worm extract submitted to purification steps (2) and, the CCA recombinant protein expressed in E. coli before (3) and after (4) induction with IPTG were subjected to silver stained SDS-PAGE analysis. Electrophoresis was done using 12% Tris-glycine gels. Molecular weight standards are shown in (1).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585039&req=5

pntd-0002054-g001: SDS-PAGE analysis of the “crude antigen” and the protein chain of recombinant CCA.Aliquots of samples corresponding to the final product of adult worm extract submitted to purification steps (2) and, the CCA recombinant protein expressed in E. coli before (3) and after (4) induction with IPTG were subjected to silver stained SDS-PAGE analysis. Electrophoresis was done using 12% Tris-glycine gels. Molecular weight standards are shown in (1).
Mentions: Four different forms of CCA were obtained and tested in IMS assays. Initially, the “crude antigen” was obtained from adult worm extracts and the CCAr were induced in E. coli. Final products are shown on Figure 1 and both demonstrated a 30 kDa protein, correlating with previously reported characteristics of CCA [25].

Bottom Line: In our previous investigations, the use of crude antigens led to false-positive results.Recently, focus has been given to highly purified Schistosoma mansoni antigens, especially to circulating antigens.Interestingly, the "crude antigen" worked as a good marker for control of cure after praziquantel treatment.

View Article: PubMed Central - PubMed

Affiliation: Schistosomiasis Laboratory, Rene Rachou Research Center, Oswaldo Cruz Foundation (Fiocruz), Belo Horizonte, Minas Gerais, Brazil.

ABSTRACT

Background: Schistosomiasis mansoni is a debilitating and sometimes fatal disease. Accurate diagnosis plays a key role in patient management and infection control. However, currently available parasitological methods are laborious and lack sensitivity. The selection of target antigen candidates has turned out to be a promising tool for the development of more sensitive diagnostic methods. In our previous investigations, the use of crude antigens led to false-positive results. Recently, focus has been given to highly purified Schistosoma mansoni antigens, especially to circulating antigens.

Method: Thus, our main goal was to test different types of circulating cathodic antigen glycoprotein (CCA), as "crude antigen," the protein chain of recombinant CCA and two individual peptides. These schistosome proteins/peptides were tested in a new diagnostic method employing immunomagnetic separation based on the improvement of antigen-antibody binding.

Principal findings: Use of recombinant CCA as a diagnostic antigen allowed us to develop a diagnostic assay with high sensitivity and specificity with no false-negative results. Interestingly, the "crude antigen" worked as a good marker for control of cure after praziquantel treatment.

Conclusions/significance: Our new diagnostic method was superior to enzyme-linked immunosorbent assay in diagnosing low endemicity patients.

Show MeSH
Related in: MedlinePlus