A cDNA library was constructed from Trichinella pseudospiralis muscle larvae. One
cDNA clone, designated Tp4, contained a
cDNA transcript of 783 bp in length, with a single open reading frame that encoded 153
amino acids (16,793 Da as the estimated molecular mass). The predicted amino acid sequence of Tp4 showed that the clone had a
calponin homology domain and was approximately 50% identical to the
transgelin-like
proteins (
calponin-family members) present in Bombyx mori or Tribolium castaneum. A homologue of the Tp4 clone was also present in
cDNA from Trichinella spiralis, and this clone was designated Ts4. A comparison of the amino acid sequence of the
transgelin-like
proteins from T. spiralis (Ts4
protein) with the Tp4
protein indicated that the two
proteins are very similar (about 94% homology). Real time quantitative polymerase chain reaction results showed that the transcription level of the Tp4 and Ts4 genes was highest in newborn larvae. On Western blot, the recombinant Tp4 and Ts4
proteins migrated at 20 kDa when reacted to an antibody against the recombinant Tp4 and Ts4
proteins, respectively. An antibody against the recombinant Tp4 and Ts4
proteins strongly stained two bands migrating at approximately 9 and 8 kDa in the
crude extracts from adult worms and newborn larvae, but only weakly stained
proteins in muscle larvae. However, an immunocytochemical study showed that the Tp4
protein was present within the muscle of the muscle larvae of T. pseudospiralis. The antibody level against the recombinant Tp4
antigens in infected mice began to increase from 8 days post-
infection, was highest in 13 days post-
infection, and then slowly decreased.