Cloning of the gene encoding a Schistosoma mansoni antigen homologous to human Ro/SS-A autoantigen.
A cDNA library was constructed from the mRNA of adult worms of Schistomsoma mansoni in the expression vector lambda gt11 and screened with a rabbit antiserum raised against a 60-65-kDa electroeluted adult worm fraction. Two overlapping clones were selected and a partial nucleotide sequence was deduced (1172 bp). The full-length sequence was obtained by the amplification of the 5' end of first strand cDNA using PCR. The overall mRNA size was 1335 nt including a 25 nt 5' non-coding region and a 131 nt untranslated region with the poly(A) tail. The predicted amino acid sequence of 393 aa (45 kDa) has 52% identity with the human Ro/SS-A autoantigen, which is considered to be the human calreticulin. As for the human Ro/SS-A, the protein encoded by the cDNA described here contains a hydrophobic leader sequence and a carboxyl terminal sequence, HDEL consensus signal sequence for retention in the ER. An antiserum raised against the fusion protein of one clone recognized a 58-kDa antigen in homogenates of cercariae and of adult worms. The expression of the protein in the pGEX-2T fusion system allowed us to show the presence of specific antibodies in S. mansoni infected patients' sera and in the sera of patients with systemic lupus erythematosus, reflecting a cross-immunoreactivity between the S. mansoni protein and the human calreticulin autoantigen.
Khalife
J
J
Centre d'Immunologie et de Biologie Parasitaire, Unité Mixte INSERM U167-CNRS URA 624, Institut Pasteur, Lille, France.
Trottein
F
F
Schacht
A M
AM
Godin
C
C
Pierce
R J
RJ
Capron
A
A
D000595:Amino Acid Sequence; D000818:Animals; D000947:Antigens, Helminth / Q000235:genetics*; D001324:Autoantigens / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D017238:Genes, Helminth; D006801:Humans; D008969:Molecular Sequence Data; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins / Q000235:genetics; D012550:Schistosoma mansoni / Q000235:genetics* / Q000276:immunology*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D000099207:SS-A Antigen
D000947:Antigens, Helminth; D001324:Autoantigens; D004247:DNA; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000099207:SS-A Antigen; C116006:RO60 protein, human