Molecular and enzymatic characterisation of Schistosoma mansoni thioredoxin.
Defense against oxidative damage can be mediated through glutathione and/or thioredoxin utilising systems. Here, we report the identification and characterisation of a thioredoxin from Schistosoma mansoni. The predicted protein has similarity to previously characterised thioredoxins including conservation of the redox active site. Recombinant six-histidine tagged schistosome thioredoxin had insulin reduction activity and supported the enzymatic function of thioredoxin reductase and thioredoxin peroxidase. By Western blotting, all mammalian stages of the schistosome lifecycle expresses thioredoxin. Thioredoxin is present in egg secretory products and antibodies against the recombinant protein produce the circumoval precipitin reaction. This is the first identification of defined antigen producing this reaction. Furthermore, thioredoxin is a novel egg immunogen as it elicits an antibody response in schistosome-infected mice. The most significant IgG production against thioredoxin occurs after parasite oviposition commences. These observations suggest that thioredoxin participates in processes vital to the parasite and may facilitate the passage and survival of eggs across inflamed host tissues.
Department of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA.
Heather M
HM
Alger
Ahmed A
AA
Sayed
Miguel J
MJ
Stadecker
David L
DL
Williams
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D003001:Cloning, Molecular; D015801:Helminth Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism*; D008018:Life Cycle Stages; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D010270:Parasite Egg Count; D010544:Peroxidases / Q000378:metabolism; D061105:Peroxiredoxin III; D054464:Peroxiredoxins; D011233:Precipitin Tests; D011994:Recombinant Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism; D012550:Schistosoma mansoni / Q000235:genetics / Q000254:growth & development / Q000276:immunology; D012555:Schistosomiasis mansoni / Q000473:pathology; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013880:Thioredoxin-Disulfide Reductase / Q000378:metabolism; D013879:Thioredoxins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism*
D015801:Helminth Proteins; D009363:Neoplasm Proteins; C516116:Prdx3 protein, mouse; D011994:Recombinant Proteins; D013879:Thioredoxins; D010544:Peroxidases; D061105:Peroxiredoxin III; D054464:Peroxiredoxins; D013880:Thioredoxin-Disulfide Reductase