Application of all-trans ethyl retinoate in preparation of immunologic adjuvant, and adjuvant and vaccine thereof

The invention discloses application of all-trans ethyl retinoate in preparation of an adjuvant for enhancing mucosal immune response as well as the adjuvant and a vaccine thereof. The all-trans ethyl retinoate can be independently used or wrapped by a formed oil-in-water type nano-emulsion adjuvant system; under the same dosage, the all-trans retinoic acid ethyl ester or the all-trans retinoic acid ethyl ester nano-emulsion adjuvant can promote the specific mucosal immune response of the stomach, the intestinal tract and the vagina, and the effect of the all-trans retinoic acid ethyl ester nano-emulsion adjuvant is obviously superior to that of all-trans retinoic acid ethyl ester. Besides, all-trans retinoic acid, all-trans retinoic acid ethyl ester and all-trans retinoic acid ethyl ester nano-emulsion adjuvant are combined with helicobacter pylori protective antigen UreB, so that the level of UreB specific sIgA antibody in the stomach and intestinal tract of a mouse can be remarkably improved, helicobacter p