The Use of Recombinant 31 kDa Antigens of Trichinella spiralis for Serodiagnosis of Experimental Trichinellosis

We have previously reported that a 31 kDa protein was screened from the excretory-secretory (ES) proteins of Tichinella spiralis muscle larvae (ML) by immunoproteomics using early infection sera, and the gene encoding a 31 kDa protein from T. spiralis was cloned and expressed in an E. coli expression system. In this study, the recombinant 31 kDa antigens were used for detection of anti-Trichinella antibodies in serum of experimentally infected mice by ELISA. Anti-Trichinella IgG antibodies in sera of mice infected with Trichinella were assayed by ELISA with recombinant 31 kDa antigens, and its sensitivity and specificity were compared with ELISA with ES antigen. The sensitivity and specificity of ELISA with recombinant antigens was 96.67% (29/30) and 96.87% (62/64), compared with 100% (30/30) and 98.44% (63/64) of ELISA with ES antigens was (P＞0.05). In heavily, moderately and lightly infected mice (500, 300 and 100 larvae/mouse), anti-Trichinella antibodies were firstly detected by ELISA with recombinant antigens at 8, 12 and 14 dpi, respec­tively; then increased rapidly with a detection rate of 100% respectively at 28, 22 and 30 dpi. While the antibodies were firstly detected by ELISA with ES anti­gens at 10, 8 and 10 dpi, respectively, the antibody positive rate reached 100% at 14, 12 and 22 dpi, respectively. The recombinant 31 kDa antigens of T. spirali had a good sensitivity and specificity for detecting anti-Trichinella antibodies and might be the potential diagnostic antigen for trichinellosis.