The J‐LEAPS vaccines contain a peptide from β‐2‐microglobulin covalently attached to disease‐related peptides of 8–30 amino acids which contain a T cell epitope. The J‐LEAPS vaccines can initiate a protective Th1 immune response or modulate an ongoing Th17 autoimmune response to the peptide. J‐LEAPS vaccines activate and direct the nature of the subsequent immune response by promoting the maturation of precursor cells into a unique type of dendritic cell that produces interleukin 12, but not IL‐1 or tumour necrosis factor, and presents the antigenic peptide to T cells. Adoptive transfer of JgD‐LEAPS dendritic cells, matured with an anti‐HSV‐1 vaccine, promoted antigen‐specific Th1 protection against lethal challenge with the virus. J‐LEAPS peptide immunogens and J‐LEAPS dendritic cell vaccines have potential applications for antimicrobial prevention and therapy, treatment of autoimmune diseases, and for cancer immunotherapy.