| Toxoplasma gondii is an obligate intracellular parasite that can infect almost all species of warm-blooded animals, and causing severe toxoplasmosis worldwide. Toxoplasmosis can be life-threatening to pregnant women and immunodeficiency individuals. No available chemical treatments could fully cure the disease, and thus T. gondii vaccine may be an ideal choice.To evaluate if T. gondii TRXL gene and ENO2 gene could be used as vaccine candidates, specific primers were designed on the basis of sequences of T. gondii in Gen Bank, and TRXL gene and ENO2 gene were amplified by RT-PCR. The products were then cloned into p ET-30a(+) vector and sequenced.The recombinant plasmid p ET-30a(+)-TRXL and p ET-30a(+)-ENO2 were then transformed in E. coli BL21 competent cells and induced by IPTG for expression. The result revealed that the ORF of TRXL gene was 1 275 bp in length, encoding 424 amino acids. BLAST analysis showed that the obtained TRXL sequence was identical to the corresponding sequence from T. gondii ME49 strain. The size of the recombinant protein TRXL was about 48 k D. The ORF of ENO2 gene was 1 335 bp, encoding 444 amino acids. BLAST analysis showed that nucleotide similarity of the obtained ENO2 sequence to T.gondii ME49 strain is 99.8%.Western Blotting analysis indicated that the recombinant protein TRXL and ENO2 could be recognized by serum from pig infected with T. gondii.In order to evaluate the effects of TRXL and ENO2, we amplified and prokaryotic express those two genes, and then emulsified the purified TRXL, ENO2, and the mixed r TRXL+r ENO2 protein with Freund’s adjuvant to construct protein vaccines. The protein vaccines were used to immunize BALB/c mice. After immunization, the three vaccines could induce strong immune responses and generate protective immunity against acute T. gondii infection in mice. The present study suggests that T. gondii TRXL protein and ENO2 protein may be ideal candidates for vaccines of toxoplasmosis. |
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