title: Molecular characterization of Schistosoma japonicum tegument protein tetraspanin-2: sequence variation and possible implications for immune evasion.
abstract: Members of tetraspanin family expressed on the tegument of Schistosoma mansoni have been regarded as potential protective antigens. In this work, we were surprised to identify seven tetraspanin-2 (TSP-2) homologs of the protective antigen Sm-TSP-2 in Schistosoma japonicum and found that the transcription profiles of Sj-tsp-2 subclasses were highly variable in individual adult worms. RT-PCR revealed that Sj-tsp-2 genes were transcribed in cercariae, schistosomula, adult worms, and eggs; however, Western blot analysis indicated that the Sj-TSP-2 proteins were not expressed in eggs. Immunolocalization assays showed that the Sj-TSP-2 proteins localized on the tegument of schistosomula and adult worms, but exposed only on the surface of adult worms. Mice immunized with the recombinant protein of a single TSP-2 subclass showed no protection, while immunized with a mixture of seven recombinant TSP-2 subclasses provided a moderate protection. Those data implicate that the tegument protein Sj-TSP-2 is involved in immune evasion and the high polymorphism of this molecule must affect its potential as a vaccine candidate.
authors.affiliation: Laboratory of Parasitology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5# Dong Dan San Tiao, Room 522, Beijing 100005, PR China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Cai
authors.forename: Lingyi
authors.initials: L
authors.lastname: Bu
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhong
authors.forename: Heng
authors.initials: H
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D005260:Female; D017238:Genes, Helminth; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D012549:Schistosoma japonicum / Q000235:genetics* / Q000254:growth & development / Q000276:immunology*; D012554:Schistosomiasis japonica / Q000517:prevention & control*; D014158:Transcription, Genetic; D014611:Vaccination; D014612:Vaccines / Q000235:genetics / Q000276:immunology
chemical_list: D015801:Helminth Proteins; D012333:RNA, Messenger; D014612:Vaccines