The follow up of Vitamin A signals in intestinal immunity.

NOVOTNY NUÑEZ I, BARRIOS BE, MACCIO-MARETTO, CORREA SG.

Buenos Aires

Congreso; 2015-IV LASID Meeting-LXIII Argentinian Society for Immunological Meeting-II French-Argentinean Immunology Meeting. 18th-21st November, Buenos Aires, Argentina.; 2015

SAI

The intestinal microenvironment modulates phenotype and activity of dendritic cells (DCs) and imprints ability to produce retinoic acid, the active metabolite of vitamin A (VA) which is critical to acquire homing receptors and to induce regulatory subsets. We studied here cells isolated from afferent lymphatics (AL) post VA administration to establish how long takes DC to acquire their competence before entering the mesenteric lymph nodes (MLN). C57BL/6 mice were feed balanced diet ad-libitum (control group) or balanced diet ad-libitum supplemented once with 5 mg VA (VA group) and AL were isolated at 3, 8, 16 and 24 post administration. Cellularity increased significantly in the VA group after 8hs (p<0.01) with higher frequency of CD11c+CD103+ DCs compared with control group. At this time an increment in CCL21 in AL was found. When co-cultured 1:1 with mononuclear cells from MLN, VA-8 AL cells were able to induce the homing integrin 47 in CD4+CFSE+ lymphocytes after 24hs. Similar experiments with inguinal lymph nodes (ILN) showed ?. Moreover, co-cultured 1:1 with sorted CD4+Foxp3- MLN from GFP-Foxp3 mice, VA-8 ALN cells were able to induce Foxp3 expression after 48 hs. Together our results show that around 8 hs after feeding VA the AL accumulate a stream of CD11c+CD103+ DCs able to imprint homing and regulatory properties to lymphocytes upon arrival to MLN.