Immune adjuvant effects of interferon-gamma (IFN-γ) of flounder (Paralichthys olivaceus) against Edwardsiella tarda

• Published in: Developmental and comparative immunology 2021-10, Vol.123, p.104159-104159, Article 104159
• Main Authors: Wang, Hongxiang, Guo, Ming, Tang, Xiaoqian, Xing, Jing, Sheng, Xiuzhen, Chi, Heng, Zhan, Wenbin
• Format: Article
• Language: English
• Subjects: Adaptive Immunity; Adjuvants, Immunologic; Animals; Antibodies; Antibodies, Bacterial - blood; Bacterial Vaccines - immunology; CD4 antigen; Cell activation; Cytokines; Edwardsiella tarda; Edwardsiella tarda - physiology; Enterobacteriaceae Infections - immunology; Fish; Fish Proteins - genetics; Fish Proteins - metabolism; Flounder; Flounder - immunology; IL-1β; Immune adjuvant; Immune response; Immune system; Immunoglobulin M; Immunoglobulins - blood; Inflammation Mediators - metabolism; Interferon; Interferon-gamma; Interferon-gamma - genetics; Interferon-gamma - metabolism; Kidneys; Lymphocyte Activation; Lymphocytes; Lymphocytes T; Major histocompatibility complex; OmpV; Paralichthys olivaceus; Peripheral blood; Spleen; Transgenes - genetics; Tumor necrosis factor-α; Vaccination; Vaccines; Vaccines, Subunit; γ-Interferon
• ISSN: 0145-305X; 1879-0089
• DOI: 10.1016/j.dci.2021.104159

IFN-γ plays a key role in T-cell activation and the establishment of the adaptive immune response, which has a potential as a cytokine adjuvant in the context of vaccination. In this study, we evaluated the immune adjuvant effects of two forms of flounder (Paralichthys olivaceus) IFN-γ, including pcDNA3.1-IFN-γ (pcIFN-γ) and recombinant IFN-γ (rIFN-γ), and comparatively analyzed the immune responses of flounder to E. tarda subunit vaccine rOmpV. The results showed that vaccination with rOmpV plus pcIFN-γ or rIFN-γ produced a relative percent survival of 57% and 71%, respectively, which were significantly higher than that of the control groups, rOmpV plus pcN3 (36%) or rHis (40%). Compared with the two control groups, vaccination with rOmpV plus pcIFN-γ or rIFN-γ could induce significantly higher levels of specific serum antibodies and sIg + lymphocytes in peripheral blood, spleen and head kidney, and significantly higher upregulated expressions of CD4-1, CD8α, IgM, MHC Ⅰα, MHC Ⅱα, IL-1β and TNF-α were also detected in rOmpV plus pcIFN-γ or rIFN-γ vaccinated fish. In addition, compared with pcIFN-γ, rOmpV co-vaccination with rIFN-γ elicited higher levels of sIg + lymphocytes, specific serum antibodies and several immune-related genes expressions in vaccinated flounder. These results demonstrated that rOmpV co-vaccination with rIFN-γ or pcIFN-γ could both boost the immune responses and evoke highly protective effects against E. tarda, indicating that flounder IFN-γ is a promising adjuvant candidate for fish vaccination via an injection administering route. •Flounder IFN-γ displayed strong adjuvant stimulatory activity.•The rIFN-γ and pcIFN-γ both can enhance the immune protective efficacy of subunit vaccines rOmpV.•Recombinant IFN-γ combined with rOmpV can elicit stronger immune response and confer higher RPS.