Development Of Fish DNA Vaccine With Fish Anaphylatoxin C5a As Adjuvant

Anaphylatoxin C5a is released during complement activation, can strongly activate a variety of inflammatory cells releasingcytokines, which have strong immune activation effect,it has great potential as a vaccine adjuvant molecules. In this paper, we immuned zebrafish with bacterial vector vaccine and DNA vaccine against fish bacterial pathogen Edwardsiella tarda with fish anaphylatoxin C5a as candidate adjuvant, the results showed C5a can improve the protective effect of the vaccine and can be used as adjuvant for the develepment of fish vaccine. In order to develop more effective fish DNA vaccine, we optimized the eukaryotic expression vector pcDNA3.1+to improve the genes expression level, making the CMV promoter be a CMV/R promoter by adding the R region of the HTLV-1LTR, and adding the woodchuck hepatitis post-transcriptional regulatory element (WPRE) to the antigen genes3’end to construct a new eukaryotic expression system pc3.1-CW, the new system can significantly enhance genes expression. Based on the optimized pc3.1-CW, we constructed candidate DNA vaccines expression of Edwardsiella tarda protective antigen ETAE-1227and zebrafish C5a molecular adjuvant. The protective effect of the vaccine and immune factor analysis in the zebrafish model showed that antigen and C5a expressing by the dicistronic system and co-expression system could effectively activate cellular immune response and humoral immune response, and over60%fish vaccinated with the two systems survived. In this study, we chose zebrafish anaphylatoxin C5a as a molecular adjuvant, optimized the eukaryotic expression system and finally developed a safe effective DNA vaccine against Edwardsiella tarda, it is important for the development offish DNA vaccine.