摘要
Objective Cell surface proteins of apicomplexan parasites are critical to the parasite in invading the host cells and stimulating the immune responses. Eimeria tenella sporozoite surface antigen 13(EtSAG13) is one of the most highly expressed soluble antigens. We previously observed an EtSAG13-specific IFN-γ secreting lymphocytes population in peripheral blood mononuclear cells(PBMCs) of E. tenella immunized chickens. However, the location of the immunogenic epitopes of EtSAG13 is unclear. Methods In this study, we cloned and expressed the N-, C-terminal and the middle part derivatives of EtSAG13(named rEtSAG13A, rEtSAG13C and rEtSAG13B, respectively), cutting the EtSAG13 into 3 equal parts, and then immunized the chickens with the peptides, respectively. These peptides of each neighbour are overlapped with 27 amino acids to cover all the possible epitopes of EtSAG13. We infected the birds by oral inoculation 200 E. tenella sporulated oocysts, and the birds were immunized with or without rEtSAG13, rEtSAG13A, rEtSAG13B or rEtSAG13C peptide twice via intramuscular injection with 2 weeks' interval. Results We found that the oocyst output of rEtSAG13-immunized birds was reduced compared with the na?ve birds after challenge infection. However, the oocyst output of rEtSAG13C(the C-terminal of EtSAG13)-immunized birds was similar to the na?ve birds, indicating that there was no immunogenic epitope in the C-terminal of EtSAG13. In contrast, the oocyst output of the N-terminal of EtSAG13(rEtSAG13 A and rEtSAG13B)-immunized birds was similar to the rEtSAG13 immunized birds that were less than the na?ve birds. Conclusion Our results were demonstrated that rEtSAG13, especially the N-terminal derivative, with good immunogenicity which encouraging its further use as a subunit vaccine against E. tenella infection.
Objective Cell surface proteins of apicomplexan parasites are critical to the parasite in invading the host cells and stimulating the immune responses. Eimeria tenella sporozoite surface antigen 13(EtSAG13) is one of the most highly expressed soluble antigens. We previously observed an EtSAG13-specific IFN-γ secreting lymphocytes population in peripheral blood mononuclear cells(PBMCs) of E. tenella immunized chickens. However, the location of the immunogenic epitopes of EtSAG13 is unclear. Methods In this study, we cloned and expressed the N-, C-terminal and the middle part derivatives of EtSAG13(named rEtSAG13A, rEtSAG13C and rEtSAG13B, respectively), cutting the EtSAG13 into 3 equal parts, and then immunized the chickens with the peptides, respectively. These peptides of each neighbour are overlapped with 27 amino acids to cover all the possible epitopes of EtSAG13. We infected the birds by oral inoculation 200 E. tenella sporulated oocysts, and the birds were immunized with or without rEtSAG13, rEtSAG13A, rEtSAG13B or rEtSAG13C peptide twice via intramuscular injection with 2 weeks' interval. Results We found that the oocyst output of rEtSAG13-immunized birds was reduced compared with the na?ve birds after challenge infection. However, the oocyst output of rEtSAG13C(the C-terminal of EtSAG13)-immunized birds was similar to the na?ve birds, indicating that there was no immunogenic epitope in the C-terminal of EtSAG13. In contrast, the oocyst output of the N-terminal of EtSAG13(rEtSAG13 A and rEtSAG13B)-immunized birds was similar to the rEtSAG13 immunized birds that were less than the na?ve birds. Conclusion Our results were demonstrated that rEtSAG13, especially the N-terminal derivative, with good immunogenicity which encouraging its further use as a subunit vaccine against E. tenella infection.
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