Assessment of the IgA and IgG response against commensal microbiota during the development of the dextran sulfate sodium-induced colitis.

LISA MACCIO MARETTO, IVANNA NOVOTNY NUÑEZ, BIBIANA E BARRIOS, AND SILVIA G CORREA

Mar del Plata

Congreso; Reunión Anual Conjunta SAIC-SAI-SAFE; 2016

SAIC-SAI-SAFE

Intestinal macrophages (MΦs) are the most abundant population of resident phagocytic cells in the gut. They can be identified by the expression of either CD11b, F4/80 or CD64 markers and play an important role in the intestinal immunity. Recently, it has been shown that IgG against commensal microbiota may contribute to the intestinal homeostasis. Herein, we evaluated the canonical IgA response as well as the production of IgG to luminal microorganisms in untreated WT mice (control group) or after 5 days of administrating dextran sulfate sodium (colitis group). During the 7 day-period of colitis development we collected feces from both groups and we analyzed IgG+ and IgA+ bacteria by flow cytometry. On day 7 of the colitis we isolated mononuclear cells from lamina propria by mild collagenase digestion and we evaluated a) the frequency of CD138+IgG+ plasmatic cells and b) the uptake of immune complexes (IgG-Ag) in CD11b+ F4/80+ permeabilized MΦs. Compared with control group the percentage of IgA-coated bacteria did not vary on colitis mice while the percentage of IgG-coated microorganisms was significantly lower with the ongoing inflammation (p