Evaluation of aqueous extracts of Cistanche deserticola as a polysaccharide adjuvant for seasonal influenza vaccine in young adult mice.

•AECD as a polysaccharide adjuvant for seasonal influenza vaccine exhibited immune enhanced activity in mice.•AECD improved immunogenicity to seasonal influenza vaccine by more rapid humoral immune responses and a balanced Th1-/Th2-type response.•AECD could improve DCs maturation and down-regulate Treg frequency.