Species-specific antibody responses to the recombinant 53-kilodalton excretory and secretory proteins in mice infected with Trichinella spp.

The 53-kDa proteins in larval excretory and secretory (E-S) products were expressed from five Trichinella species (T. spiralis, T. britovi, T. nativa, T. pseudospiralis, and T. papuae), using the Escherichia coli expression system, and the antibody responses to the 53-kDa recombinant proteins in mice infected with Trichinella spp. were analyzed by Western blotting. The 53-kDa protein is conserved among the five Trichinella species, with >60% similarity in amino acid sequences. The 53-kDa recombinant proteins of T. spiralis and T. pseudospiralis reacted to sera from mice infected with T. spiralis and T. pseudospiralis at 8 days postinfection (p.i.), respectively. An antibody against the 53-kDa recombinant protein of T. spiralis recognized the 53-kDa protein in the crude extracts from adult worms and 30-day p.i. muscle larvae and E-S products from muscle larvae of T. spiralis but did not recognize any proteins from T. pseudospiralis. The sera from the mice infected with T. spiralis strongly reacted with the 53-kDa recombinant protein of T. spiralis but did not react with the 53-kDa recombinant proteins of T. britovi, T. nativa, T. pseudospiralis, and T. papuae. Similarly, the sera from mice infected with T. britovi, T. nativa, T. pseudospiralis, or T. papuae strongly reacted with the 53-kDa recombinant proteins of T. britovi, T. nativa, T. pseudospiralis, or T. papuae, respectively. These results showed that the 53-kDa recombinant proteins provide early and species-specific antibody responses in mice infected with Trichinella spp.