Galectin-8 activates dendritic cells and stimulates antigen-specific immune response

CARABELLI, JULIETA; PRATO, CECILIA ARAHÍ; VALERIA QUATTROCCHI; ALEJANDRA D'ANTUONO; PATRICIA ZAMORANO; TRIBULATTI MARÍA VIRGINIA; CAMPETELLA, OSCAR

Villa Gral Belgrano, Córdoba

Simposio; 2nd Argentinean Symposium on Glycobiology; 2016

Sociedad Latinoamericana de Glicobiología

Galectin-8 (Gal-8) is a mammalian beta-galactoside-binding lectin, endowed with pro-inflammatory properties. Given its capacity to enhance antigen-specific immune responses in vivo, we investigated whether Gal-8 was also able to promote antigen-presenting cells activation to sustain T cell activation after priming. Dendritic cells (DC) treated with exogenous Gal-8 exhibited a mature phenotype characterized by increased MHC II, CD80 and CD86 surface expression. Moreover, DC activated in the presence of Gal-8 stimulated antigen-specific T cells more efficiently than immature DC. Several pro-inflammatory cytokines like IL-3, IL-2, IL-6, TNF-α, MCP-1 and MPC-5, as well as growth factor G-CSF, were augmented in Gal-8-treated DC conditioned media, being IL-6 the most abundant. Remarkably, DC from Gal-8-deficient mice (DCLgal8-/-) displayed reduced CD86 and IL-6 expression, and were less efficient to promote antigen-specific CD4 T cell activation. In order to test if Gal-8-induced activation correlates with the elicitation of an effective immune response, soluble Gal-8 was co-administrated with antigen during immunization of BALB/CJ mice in the experimental Foot-and-Mouth Disease Virus model. When a single dose of Gal-8 was added to the antigen formulation, an increased specific and neutralizing humoral response was developed, sufficient to enhance animal protection upon viral challenge. IL-6 and INF-γ as well as lymphoproliferative responses were also incremented in Gal-8-antigen immunized animals at early times after immunization (48h), suggesting that Gal-8 participates in the elicitation of the immune response. Taking together, these findings argue in favour of the use of Gal-8 as an immune-stimulator molecule to enhance the adaptive immune response.