Effects of immune response on different nano-adjuvants combined with H11 antigen of Haemonchus contortus.

The intestinal native protein H11 is one of the most immunodominant antigen of Haemonchus contortus. However, H11 combined with QuilA adjuvant shows only short-lived protection for animals. Nano-adjuvants have the huge potential to extend the immune response in human and animals. Here, we compared the immune responses induced by H11 combined with three nano-adjuvants including lipid nanoparticles (LNP), immunostimulating complex matrix (IMX) and AddaS03™. We measured the cytokine levels of goat PBMCs stimulated by H11 mixed with three nano-adjuvants and QuilA. Results showed that the transcriptions of IL-6, IL-8 and IFN-γ genes were significantly inhibited in all adjuvant group compared with PBS control. H11-IMX combination significantly up-regulated IL-2, IL-17 and TNF-α gene transcriptions. The H11-LNP group showed a significant increase in IL-17 and TNF-α transcriptions, while the H11-AddaS03™ group significantly increased IL-2 transcription. Additionally, mice immunized with these formulations were assessed for splenic lymphocyte proliferation. All H11-adjuvant combinations, except H11-LNP, significantly stimulated lymphocyte proliferation compared to the H11 alone and PBS control groups, with the H11-AddaS03™ combination showing the strongest effect. Analysis of serum antibody levels revealed that all immune groups induced high IgM levels, with H11-IMX inducing the highest IgG levels. Our results demonstrated that IMX or LNP combined with H11 mainly induced a Th17 cell immune response in goat PBMCs, while IMX or AddaS03™ combined with H11 could induce a strong humoral immune response in mice. This study elucidates the immune response profiles of different nano-adjuvant combined with H11 antigen, providing important insights for vaccine development against parasitic nematodes.