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DNA vaccine encoding molecular chaperone GroEL of Edwardsiella tarda confers protective efficacy against edwardsiellosis
- Liu, Fuguo, Tang, Xiaoqian, Sheng, Xiuzhen, Xing, Jing, Zhan, Wenbin
- Molecular Immunology 2016 v.79 pp. 55-65
- Edwardsiella tarda, Paralichthys olivaceus, antibodies, blood serum, flounder, immune response, interleukin-1beta, lymphocytes, messenger RNA, molecular chaperones, protective effect, recombinant vaccines, spleen, transfection, tumor necrosis factor-alpha, vaccination
- In the present study, molecular chaperone GroEL of Edwardsiella tarda was found both react with flounder (Paralichthys olivaceus) anti-recombinant GroEL (rGroEL) and anti-E. tarda antibodies, and it was both detected in the outer membrane and the secretome. To evaluate the vaccine potential of GroEL, pCI-neo-GFP-GroEL (pCG-GroEL) was prepared and used to vaccinate healthy flounder, and immune protective effects were investigated. The results showed that pCG-GroEL produced an RPS of 60% following E. tarda challenge at week 5 after immunization. Moreover, GroEL transcripts and GFP-tagged GroEL could be detected in vaccinated flounder after immunization with pCG-GroEL, and the GFP-tagged GroEL could be also detected in HINAE cells after transfection with pCG-GroEL. Meanwhile, the immune response of flounder induced by pCG-GroEL was investigated, and the results showed that: (1) the levels of specific serum antibodies against E. tarda induced by pCG-GroEL were significantly higher than other groups at 3–5 week post vaccination; (2) pCG-GroEL could induce the proliferation of sIg+ lymphocytes, and the levels of sIg+ lymphocytes in blood, spleen and pronephros of pCG-GroEL vaccinated fish were significantly increased compared with the PBS vaccinated fish at 3w, 2w and 2w after immunization, respectively; (3) MHCIα, MHCIIα, CD4-1, CD8α, IL-1β and TNF-α were significantly induced by immunization with pCG-GroEL, and the mRNA levels of CD4-1 and CD8α rapidly increased in pCG-GroEL vaccinated fish after challenge with E. tarda. Taking together, pCG-GroEL could elicit highly protective effects against E. tarda and induce strong immune response of flounder, suggesting that GroEL was a promising vaccine candidate.