The immune-adjuvant effect of Japanese flounder Paralichthys olivaceus IL-1β.

IL-1β is known as a pro-inflammatory cytokine and plays a pivotal role in regulating immune response. IL-1β has been shown to influence immune responses in Japanese flounder Paralichthys olivaceus. To investigate the immune responses, a plasmid construct of pcDNA3.1-driven Japanese flounder IL-1β (pcDNA3.1-JFIL-1β) was co-injected into the muscle with Bovine serum albumin (BSA), as an antigen model, or pCI-neo driven with GFP (pCI-neo-GFP) as a vaccine model compared with the antigen or vaccine model alone, respectively. The IL-1β expression in the muscle was dramatically elevated in fish injected with pcDNA3.1-JFIL-1β on a day after injection, and the induction level was significantly higher than control groups. Moreover, pcDNA3.1-JFIL-1β significantly stimulated the gene expression of IL-1β in the kidney. The pcDNA3.1-JFIL-1β enhanced the antibody titer against BSA at 30 days after injection. In the DNA vaccine model, the antibody titer against GFP was also higher in the fish injected with pcDNA3.1-JFIL-1β than the group that injected pCI-neo-GFP alone. These results suggest that the pcDNA-driven Japanese flounder IL-1β could have potential immunoadjuvant effects.