Expression analysis of three immune genes IL-8, IL-6 and IL-1β in the Japanese flounder (Paralichthys olivaceus)

Abstract

Interleukin-8 (IL-8), Interleukin-6 (IL-6), and Interleukin-1β (IL-1β) are major immune-related genes that play important roles in the innate immune system of vertebrates. In this study, the expression levels of the three immune-related genes in eleven tissues of normal adult Japanese flounder (Paralichthys olivaceus) were examined using semi-quantitative RT-PCR at 13time points after challenge with Lipopolysaccharide (LPS). The results showed that the highest expression levels of the Japanese flounder IL-8 were detected at 12h in the spleen, 12h in the head kidney, and 24h in the liver after the challenge with LPS. Interestingly, the expression levels of IL-6 in the spleen and head kidney were highest at 48h. The liver had the highest expression level of IL-6 at 36h.The highest expression levels of IL-1β were detected at 3h in the spleen and 9h in the head kidney and liver. These results indicated that IL-8, IL-6, and IL-1β also played important roles in the immune response of the Japanese flounder at lower temperatures. The study provided a basis for further research on the immune mechanisms of IL-8, IL-6, IL-1β, and the production of recombinant IL-8, IL-6, or IL-1β used in Japanese flounder cultivation.