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.