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

Abstract

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.

FIG. 1.

Deduced amino acid sequences of the 53-kDa proteins of T. spiralis (GenBank accession number AAA97512), T. britovi (GenBank accession number CAD86782), T. nativa (GenBank accession number DQ399908), T. pseudospiralis (GenBank accession number AAK29415), and T. papuae (GenBank accession number DQ399909). Amino acid residues conserved in all five sequences are indicated by asterisks. The putative signal peptides are indicated in boldface. The numbers along the margin designate the positions of amino acid residues.

FIG. 2.

Western blot analysis of crude extracts from T. spiralis adult worms (lane 1), T. spiralis newborn larvae (lane 2), T. spiralis 15-day p.i. muscle larvae (lane 3), T. spiralis 30-day p.i. muscle larvae (lane 4), E-S products from T. spiralis muscle larvae (lane 5), crude extracts from T. pseudospiralis adult worms (lane 6), T. pseudospiralis newborn larvae (lane 7), T. pseudospiralis 15-day p.i. muscle larvae (lane 8), T. pseudospiralis 30-day p.i. muscle larvae (lane 9), and E-S products from T. pseudospiralis muscle larvae (lane 10) immunostained with antibody against the T. spiralis 53-kDa recombinant protein (A) or immunostained with antibody against the T. pseudospiralis 53-kDa recombinant protein (B). M, molecular mass standards; sizes in kDa are shown on the left side.

FIG. 3.

(A) Western blot analysis of the T. spiralis 53-kDa recombinant protein immunostained with sera from noninfected mice (lane 1) or sera from mice infected with T. spiralis at 8 days p.i. (lane 2), 13 days p.i. (lane 3), 18 days p.i. (lane 4), 23 days p.i. (lane 5), 30 days p.i. (lane 6), 50 days p.i. (lane 7), 90 days p.i. (lane 8), and 120 days p.i. (lane 9). (B) Western blot analysis of the T. pseudospiralis 53-kDa recombinant protein immunostained with sera from noninfected mice (lane 1) or sera from mice infected with T. pseudospiralis at 8 days p.i. (lane 2), 13 days p.i. (lane 3), 18 days p.i. (lane 4), 23 days p.i. (lane 5), 30 days p.i. (lane 6), 50 days p.i. (lane 7), 90 days p.i. (lane 8), and 120 days p.i. (lane 9).

FIG. 4.

(A) SDS-PAGE analysis of the purified 53-kDa recombinant proteins of T. spiralis (lane 1), T. pseudospiralis (lane 2), T. nativa (lane 3), T. papuae (lane 4), and T. britovi (lane 5). (B to F) Cross-reactivity analysis by Western blotting results with the 53-kDa recombinant proteins of T. spiralis (lane 1), T. pseudospiralis (lane 2), T. nativa (lane 3), T. papuae (lane 4), and T. britovi (lane 5) immunostained with sera from mice infected with T. spiralis (B), T. pseudospiralis (C), T. nativa (D), T. papuae (E), or T. britovi (F). M, molecular mass standards; sizes in kDa are shown on the left side.