Agricultural Adjuvant Manufacturers describes the role of adjuvants:

(1) Convert non-antigenic substances into effective antigens;
(2) Enhance the level of circulating antibodies or generate more effective protective immunity;
(3) changing the type of circulating antibodies produced;
(4) the ability to enhance cell-mediated hypersensitivity;
(5) produce experimental autoimmunity or other types of allergic diseases;
(6) Protect antigens (especially DNA, RNA) from decomposing by enzymes in vivo.