Newly established monoclonal antibody diagnostic assays for Schistosoma mansoni direct detection in areas of low endemicity.
BACKGROUND
Current available methods for diagnosis of schistosomiasis mansoni lack sufficient sensitivity, which results in underreporting of infectious in areas of low endemicity.


RESULTS
We developed three novel diagnostic methodologies for the direct detection of schistosome infection in serum samples. These three new methods were evaluated with positive patients from a low endemicity area in southeast Brazil. The basis of the assay was the production of monoclonal antibodies against the protein backbone of heavily glycosylated Circulating Cathodic Antigen (CCA). The antibodies were also selected for having no specificity to repeating poly-Lewis x units. Assays based on the detection CCA-protein should not encounter a limitation in sensitivity due to a biological background of this particular epitope. Three diagnostic methodologies were developed and validated, (i) Immunomagnetic Separation based on improved incubation steps of non-diluted serum, (ii) Direct Enzyme-linked Immunosorbent Assay and (iii) Fluorescent Microscopy Analysis as a qualitative assay. The two quantitative assays presented high sensitivity (94% and 92%, respectively) and specificity (100%), equivalent to the analysis of 3 stool samples and 16 slides by Kato-Katz, showing promising results on the determination of cure.


CONCLUSIONS
The Immunomagnetic Separation technique showed excellent correlation with parasite burden by Cohen coefficient. The qualitative method detected 47 positive individuals out of 50 with the analysis of 3 slides. This easy-to-do method was capable of discriminating positive from negative cases, even for patients with low parasite burden.
Schistosomiasis Laboratory, Rene Rachou Research Center, Oswaldo Cruz Foundation (Fiocruz), Belo Horizonte, Minas Gerais, Brazil ; Department of Infectious Diseases, College of Veterinary Medicine, and Center for Tropical and Emerging Global Diseases, University of Georgia (UGA), Athens, Georgia, United States of America.
Rafaella Fortini Queiroz
RF
Grenfell
Schistosomiasis Laboratory, Rene Rachou Research Center, Oswaldo Cruz Foundation (Fiocruz), Belo Horizonte, Minas Gerais, Brazil.
Paulo Marcos Zech
PM
Coelho
Schistosomiasis Laboratory, Rene Rachou Research Center, Oswaldo Cruz Foundation (Fiocruz), Belo Horizonte, Minas Gerais, Brazil.
Diana
D
Taboada
Schistosomiasis Laboratory, Rene Rachou Research Center, Oswaldo Cruz Foundation (Fiocruz), Belo Horizonte, Minas Gerais, Brazil.
Ana Carolina Alves
AC
de Mattos
Monoclonal Antibody Facility, College of Veterinary Medicine, University of Georgia (UGA), Athens, Georgia, United States of America.
Ruth
R
Davis
Department of Infectious Diseases, College of Veterinary Medicine, and Center for Tropical and Emerging Global Diseases, University of Georgia (UGA), Athens, Georgia, United States of America.
Donald A
DA
Harn
D000328:Adult; D000368:Aged; D000818:Animals; D000909:Antibodies, Helminth / Q000737:chemistry* / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000276:immunology; D000947:Antigens, Helminth / Q000097:blood* / Q000276:immunology; D005260:Female; D006023:Glycoproteins / Q000097:blood* / Q000276:immunology; D015801:Helminth Proteins / Q000097:blood* / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012550:Schistosoma mansoni; D012555:Schistosomiasis mansoni / Q000097:blood* / Q000276:immunology
D000909:Antibodies, Helminth; D000911:Antibodies, Monoclonal; D000947:Antigens, Helminth; C091532:CCA protein, Schistosoma mansoni; D006023:Glycoproteins; D015801:Helminth Proteins