Cytokine mediated immune responses in the Japanese pufferfish (Takifugu rubripes) administered with heat-killed Lactobacillus paracasei spp. paracasei (06TCa22) isolated from the Mongolian dairy product

The important role played by cytokines in host innate immunity and the interaction of subsets of immune and inflammatory cells through cytokines offer avenues for immune interventions. We investigated 16 cytokine gene responses in the Japanese pufferfish, Takifugu rubripes orally treated with a heat-killed lactic acid bacterium (LAB), Lactobacillus paracasei spp. paracasei (strain 06TCa22) (Lpp) isolated from a Mongolian dairy product at 1 mg g− 1 body weight d− 1 for 3 days. Additionally, we assessed superoxide anion production (SAP) and phagocytic activity (PA) of head kidney cells and resistance to Vibrio harveyi infection in treated fish. Significant up-regulation of pro-inflammatory (IL-1β, IL-6, IL-17A/F-3, TNF-α and TNF-N), cell-mediated immunity inducing (IL-12p35, IL-12p40 and IL-18), antiviral/intra-cellular pathogen killing (I-IFN-1 and IFN-γ), anti-inflammatory (IL-10) and peripheral T cell expansion and survival controlling (IL-2, IL-7, IL-15, IL-21 and TGF-β1) cytokines was observed in the treated fish. Furthermore, significantly increased SAP, PA and pathogen resistance were observed in the treated fish compared to untreated fish. Our results indicate the enhancement of cytokine mediated immunity in T. rubripes by the use of the heat-killed Lpp as a potential immunostimulant and would be of great use in immunomodulation trials with the possibility to monitor positive immune response.