The present invention is an antigen-and-drug (AD) vehicle and a mucosal vaccine utilizing a novel synthetic peptide. The antigen-and-drug (AD) vehicle is capable of inducing the production of secretory IgA antibodies, and is a complex of a synthetic peptide having the following amino acid sequence: PVHLKRLm (e.g., peptide of SEQ ID NO 1, 6, or 7) or KnLm (e.g., peptide of SEQ ID NO 2, 3, or 8), and a lipid(s). The mucosal vaccine is obtainable by allowing a mucosal-immunity-IgA-inducing amount of an antigen to coexist with, contact, be captured by, or be adsorbed onto the AD vehicle.
