title: Retinoic acid induces homing of  protective T and B cells to the gut after  subcutaneous immunization in mice.
abstract: Diarrheal diseases represent a major health burden in developing countries. Parenteral immunization typically does not induce efficient protection against enteropathogens because it does not stimulate migration of immune cells to the gut. Retinoic acid (RA) is critical for gut immunity, inducing upregulation of gut-homing receptors on activated T cells. In this study, we have demonstrated that RA can redirect immune responses elicited by s.c. vaccination of mice from skin-draining inguinal LNs (ingLNs) to the gut. When present during priming, RA induced robust upregulation of gut-homing receptors in ingLNs, imprinting gut-homing capacity on T cells. Concurrently, RA triggered the generation of gut-tropic IgA+ plasma cells in ingLNs and raised the levels of antigen-specific IgA in the intestinal lumen and blood. RA applied s.c. in vivo induced autonomous RA production in ingLN DCs, further driving efficient induction of gut-homing molecules on effector cells. Importantly, RA-supplemented s.c. immunization elicited a potent immune response in the small intestine that protected mice from cholera toxin–induced diarrhea and diminished bacterial loads in Peyer patches after oral infection with Salmonella. Thus, the use of RA as a gut-homing navigator represents a powerful tool to induce protective immunity in the intestine after s.c. immunization, offering what we believe to be a novel approach for vaccination against enteropathogens.
authors: Institute of Immunology, Hannover Medical School, Hannover, Germany.
authors: Swantje I
authors: SI
authors: Hammerschmidt
authors: Michaela
authors: M
authors: Friedrichsen
authors: Jasmin
authors: J
authors: Boelter
authors: Marcin
authors: M
authors: Lyszkiewicz
authors: Elisabeth
authors: E
authors: Kremmer
authors: Oliver
authors: O
authors: Pabst
authors: Reinhold
authors: R
authors: Förster
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D018920:Coculture Techniques; D007107:Immune System; D007114:Immunization; D007279:Injections, Subcutaneous; D007413:Intestinal Mucosa / Q000378:metabolism; D008197:Lymph Node Excision / Q000379:methods; D008198:Lymph Nodes / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009092:Mucous Membrane / Q000473:pathology; D010581:Peyer's Patches; D012475:Salmonella / Q000378:metabolism; D012480:Salmonella Infections / Q000378:metabolism; D012867:Skin / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D014212:Tretinoin / Q000378:metabolism*
chemical_list: D014212:Tretinoin