Galectin-glycan interactions at the crossroads between commensal microbiota and T cell function

MOROSI, LUCIANO; CUTINE, ANABELA; MORALES, ROSA ; BLANCATO, VICTOR; MAGNI, CHRISTIAN; MENDOZA, DIEGO DE; TOSCANO, MARTA A; RABINOVICH, GABRIEL A.; MARIÑO, KARINA

Paris

Congreso; 2nd World Congress on Targeting Microbiota 2014 / Targeting Microbiota World Congress 2014; 2014

International Society of Microbiota

The intestinal microbiota plays a crucial role in the host defense, helping to shape the immune system throughout life. A dynamic dialogue between intestinal immune cells and bacteria ensures a homeostatic immune state, which includes not only protection from pathogens but also hypo-responsiveness to environmental antigens (dietary and/or commensal antigens). In recent years, specific strains of lactic acid bacteria (LAB) showing beneficial immunological properties in both gastrointestinal and systemic levels have been used as food supplement (mostly from the genus Lactococcus and Lactobacillus). Nevertheless, the mechanisms underlying these immunomodulatory effects are not completely understood. Galectins, soluble lectins capable of recognizing N-acetyllactosamine residues in glycoconjugates, are key modulators of the immune response . There is solid evidence of their essential yet diverse roles in immunoregulation. Galectin-1 (Gal1), a member of this family, can directly induce apoptosis of TH1 and TH17 lymphocytes or activate regulatory circuits mediated by T regulatory cells (Tregs) and regulatory dendritic cells. However, little is known on how commensal microbiota affects the intestinal repertoire of galectins and the glycophenotype (exposed cell surface glycans) of epithelial and mucosa-associated immune cells. In this work we studied the effect of oral administration of three LAB (Lactococcus lactis NZ9000, Lactobacillus casei BL23 and Enteroccocus faecalis JH2-2) on the glycosylation of CD4 + and CD8 + T cells from colon (local level) and spleen (systemic level), and the gene expression of five galectins (Gal1, Gal3, Gal4, Gal8 and Gal9) relevant to the gut immune response.