{Reference Type}: Journal Article {Title}: Oral immunization with recombinant Lactobacillus casei displayed AHA1-CK6 and VP2 induces protection against infectious pancreatic necrosis in rainbow trout (Oncorhynchus mykiss). {Author}: Chen Y;Hua X;Ren X;Duan K;Gao S;Sun J;Feng Y;Zhou Y;Guan X;Li D;Wang N;Li J;Yang J;Xia D;Shi W;Liu M; {Journal}: Fish Shellfish Immunol {Volume}: 100 {Issue}: 0 {Year}: May 2020 {Factor}: 4.622 {DOI}: 10.1016/j.fsi.2020.03.001 {Abstract}: Infectious pancreatic necrosis virus (IPNV) primarily infects larvae and young salmonid with serious economic losses, which causes haemorrhage and putrescence of hepatopancreas. To develop a more effective oral vaccine against IPNV infection, the aeromonas hydrophila adhesion (AHA1) gene was used as a targeting molecule for intestinal epithelial cells. A genetically engineered Lactobacillus casei (pPG-612-AHA1-CK6-VP2/L. casei 393) was constructed to express the AHA1-CK6-VP2 fusion protein. The expression of interest protein was confirmed by western blotting and the immunogenicity of pPG-612-AHA1-CK6-VP2/L. casei 393 was evaluated. And the results showed that more pPG-612-AHA1-CK6-VP2/L. casei 393 were found in the intestinal mucosal surface of the immunized group. The Lactobacillus-derived AHA1-CK6-VP2 fusion protein could induce the production of serum IgM and skin mucus IgT specific for IPNV with neutralizing activity in rainbow trouts. The levels of IL-1β, IL-8 and TNF-α isolated from the lymphocytes stimulated by AHA1-CK6-EGFP produced were significantly higher than EGFP group. For transcription levels of IL-1β, IL-8, CK6, MHC-II, Mx and TNF-1α in the spleen, the result indicated that the adhesion and target chemokine recruit more immune cells to induce cellular immunity. The level of IPNV in the immunized group of pPG-612-AHA1-CK6-VP2/L. casei 393 was significantly lower than that in the control groups. These data indicated that the adhesion and target chemokine could enhance antigen delivery efficiency, which provides a valuable strategy for the development of IPNV recombination Lactobacillus casei oral vaccine in the future.