Simultaneous enhancement of cellular and humoral immunity by the high salt formulation of AI（OH）3 adjuvant

Dear Editor, Adjuvants play essential roles in vaccination by enhancing and/or shaping antigen-specific immune re- sponses [1]. They are commonly used in every type of vaccines, e.g., cancer vaccines, which have been proved to be a promising approach for cancer immune therapy [2]. Aluminum-based adjuvants have been widely used in human vaccination for decades [3]. Despite the robust induction of antibody-mediated immune responses, a limitation of aluminum-based adjuvants is their weak stimulation of cell-mediated immunity [4]. Thus, the de- velopment of safe, stable and effective adjuvants with the ability to enhance both humoral and cellular immune re- sponses during clinical vaccination remains challenging. As the major antigen-presenting cells （APCs） to initiate immune responses, dendritic cells （DCs） can be triggered by environmental stimulation to elicit different pheno- types and functions [5, 6]. Moreover, cross-presentation of extracellular protein antigens by DCs contributes to the generation of cytotoxic T lymphocyte （CTL） respons- es [7]. Sodium chloride （NaC1） is closely related to our daily lives and has recently been found to have potential effects on the development of autoimmune diseases [8, 9] and specific states of macrophages [10]. However, the impacts of high concentrations of salt on the functions of DCs and the immune system have not been studied. The use of high salt formulation in combination with aluminum adjuvants in protein vaccines remains to be explored.