title: Characterization of an atypical antigen from Sarcoptes scabiei containing an MADF domain.
abstract: We have cloned a cDNA encoding a novel antigen from a Sarcoptes scabiei (Acari) cDNA library by immunoscreening with sera from S. scabiei-infected dogs. The antigen is encoded by a 2,157 bp mRNA with a predicted open reading frame of 719 amino acids (molecular weight 79 kDa). Our sequence analysis identified the presence of a MADF domain in the N-terminus, and downstream of this domain there was a region of low sequence complexity. This latter region contained several blocks of triplets and quadruplets of polar amino acids (Asn, Gln and Ser), and these 3 amino acids represented 39.7% of all amino acids. The antigen was named Atypical Sarcoptes Antigen 1 (ASA1) since the MADF domain normally is found in proteins involved in transcriptional regulation. In addition, 15 out of 62 S. scabiei-infected dogs reacted with a purified recombinant version of ASA1 in Western blot analysis. With immunohistochemistry we could show that ASA1 is expressed throughout the parasite, and that IgG specific for ASA1 binds to the inside wall of the mite's burrow. To our knowledge, this is the first description of an antigen containing an MADF domain.
authors.affiliation: Department of Parasitology, SWEPAR, National Veterinary Institute and Swedish University of Agricultural Sciences, SE-751 89 Uppsala, Sweden.
authors.forename: E L
authors.initials: EL
authors.lastname: Ljunggren
authors.forename: K
authors.initials: K
authors.lastname: Bergström
authors.forename: D A
authors.initials: DA
authors.lastname: Morrison
authors.forename: J G
authors.initials: JG
authors.lastname: Mattsson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000941:Antigens / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D018076:DNA, Complementary / Q000737:chemistry* / Q000235:genetics; D005786:Gene Expression Regulation; D015723:Gene Library; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012333:RNA, Messenger / Q000737:chemistry* / Q000235:genetics; D011817:Rabbits; D012520:Sarcoptes scabiei / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D000941:Antigens; D018076:DNA, Complementary; D012333:RNA, Messenger