Henan University of Science and Technology, Luoyang, China.
J Vet Med Sci. 2023 Sep 7;85(9):964-971. doi: 10.1292/jvms.22-0579. Epub 2023 Jul 4.
Immunostimulants and vaccines are the main means for controlling infectious diseases and searching highly effective and low toxic immunestimulants has always been the focus of researchers. The MetchnikowinII (MetII) had been expressed by us and exhibited both antibacterial and antifungal activities, in this study, we evaluated its potential for an adjuvant effect. In chickens, antigen-specific immunoglobulin Gs (IgGs) were increased after MetII adjuvanted vaccination using the Ptfa protein. Compared to group Ptfa + iFA, which was only adjuvanted with incomplete Freund's adjuvant (iFA), the antibody titers of the group Ptfa + iFA + Met20 μg·mL (PFM) and Ptfa + iFA + Propolis (PFP) significantly increased (P<0.05). Likewise, Interleukin-2 (IL-2) and Interferon-γ (IFN-γ) cytokines in group Ptfa + iFA + Met20 μg·mL (PFM) and Ptfa + iFA + Propolis (PFP) were significantly higher than those of the other three experimental groups (P<0.05). The stimulation index (SI) value in chickens of group PFM was significantly higher than that of the other four experimental groups (P<0.05). Chickens that received MetII adjuvanted vaccinations benefitted from higher protection rate (88%) when challenged with Pasteurella multocida (P. multocida), which was significantly higher than those of group PF and PFP (P<0.05). These results suggested that the antimicrobial peptide MetII may play an adjuvant role in the immune response in chickens but need a proper usage, because the higher usage of 40 μg·mL and 60 μg·mL resulted poor effect. Whether MetII could be a potential adjuvant or a biomolecule as part of a complex adjuvant for vaccines needs more experimental evidence, the study still provides an examples for understanding vaccine adjuvants.
免疫刺激剂和疫苗是控制传染病的主要手段，寻找高效低毒的免疫刺激剂一直是研究人员关注的焦点。我们已经表达了 MetchnikowinII（MetII），它具有抗菌和抗真菌活性，在这项研究中，我们评估了它作为佐剂的潜力。在鸡中，MetII 佐剂接种 Ptfa 蛋白后，抗原特异性免疫球蛋白 G（IgG）增加。与仅用不完全弗氏佐剂（iFA）佐剂的 Ptfa + iFA 组相比，Ptfa + iFA + Met20μg·mL（PFM）和 Ptfa + iFA + 蜂胶（PFP）组的抗体滴度显著增加（P<0.05）。同样，Ptfa + iFA + Met20μg·mL（PFM）和 Ptfa + iFA + 蜂胶（PFP）组的白细胞介素 2（IL-2）和干扰素-γ（IFN-γ）细胞因子明显高于其他三组（P<0.05）。PFM 组鸡的刺激指数（SI）值明显高于其他四组（P<0.05）。当受到多杀性巴氏杆菌（P. multocida）攻击时，接受 MetII 佐剂接种的鸡受益于更高的保护率（88%），明显高于 PF 和 PFP 组（P<0.05）。这些结果表明，抗菌肽 MetII 可能在鸡的免疫反应中发挥佐剂作用，但需要适当使用，因为较高的 40μg·mL 和 60μg·mL 用量会导致效果不佳。MetII 是否可以作为疫苗佐剂的潜在佐剂或生物分子，或者作为复杂佐剂的一部分，需要更多的实验证据，该研究为理解疫苗佐剂提供了一个范例。
