Molecular cloning and characterisation of two kinds of proteins in excretory-secretory products of Trichinella pseudospiralis.

Two genes encoding Trichinella pseudospiralis excretory-secretory proteins related to the Trichinella spiralis glycoproteins were cloned and the excretory-secretory proteins were characterised. A cloned gene, designated Tp38 (Ts43), contained a cDNA transcript of 1035 bp, and the predicted amino acid sequence of the Tp38 (Ts43) pro-protein had a similarity of about 84% to that of the T. spiralis 43 kDa glycoprotein. A cloned gene, designated Tp53 (Ts53), contained a cDNA transcript of 1239 bp, and the predicted amino acid sequence of the Tp53 (Ts53) pro-protein had a similarity of about 68% to that of the T. spiralis 53 kDa glycoprotein. Southern blots indicated that the Tp38 (Ts43) and Tp53 (Ts53) genes were encoded in a single copy within the T. pseudospiralis genome. Western blots showed that T. pseudospiralis-infected sera recognised the Tp53 (Ts53) recombinant protein, but did not recognise the Tp38 (Ts43) recombinant protein. The Tp38 (Ts43) and Tp53 (Ts53) proteins in the excretory-secretory product were 3 and 9 kDa greater than the expected molecular mass, respectively, and had three isoforms with a similar molecular size. Reverse transcription polymerase chain reaction results showed that the production of the mRNA transcript for the Tp38 (Ts43) or Tp53 (Ts53) gene was restricted predominantly to muscle larvae. Western blots confirmed that the gene products were predominantly expressed by muscle-stage larvae. An immunolocalisation study showed the Tp38 (Ts43) and Tp53 (Ts53) proteins were present within the alpha-stichocyte and the beta-stichocyte of muscle larvae, respectively.