Molecular cloning and characterization of the polypeptide backbone of Schistosoma mansoni circulating cathodic antigen.
One of the candidate schistosome antigens for the development of a circulating antigen detection diagnostic assay is the circulating cathodic antigen (CCA). Detection of CCA in urine provides a non-invasive assay with high sensitivity. Previously we reported that CCA is secreted in patients' urine as a small molecular weight material which is probably of a proteinaceous nature. In an attempt to further characterize the secreted component of CCA, we used a monoclonal antibody (MAb) reactive with urine-CCA to isolate an adult worm cDNA clone (SmN3-1) that encodes the polypeptide backbone of CCA. The sequence, gene organization and expression of SmN3-1 were analyzed. The 1.6 kb nucleotide and 347 amino acid sequences of SmN3-1 showed no significant homology to any published sequence. The size and antigenic properties of the expression product of SmN3-1 in Escherichia coli greatly resembled the CCA molecule excreted in urine, suggesting that the latter is primarily composed of the protein element of CCA.
Abdeen
H H
HH
US Naval Medical Research Unit No.3, Cairo, Egypt. boushrah@namru3.navy.mil
Attallah
A F
AF
Mansour
M M
MM
Harrison
R A
RA
D000595:Amino Acid Sequence; D000818:Animals; D000947:Antigens, Helminth / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics* / Q000652:urine; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018509:DNA, Helminth / Q000235:genetics; D017125:Genes, Protozoan; D006023:Glycoproteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics* / Q000652:urine; D015801:Helminth Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics* / Q000652:urine; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry; D012550:Schistosoma mansoni / Q000235:genetics / Q000254:growth & development / Q000276:immunology*; D012555:Schistosomiasis mansoni / Q000469:parasitology; D017422:Sequence Analysis, DNA
D000947:Antigens, Helminth; C091532:CCA protein, Schistosoma mansoni; D018076:DNA, Complementary; D018509:DNA, Helminth; D006023:Glycoproteins; D015801:Helminth Proteins; D010455:Peptides; D011993:Recombinant Fusion Proteins