Complementary function of gamma delta T-lymphocytes and dendritic cells in the response to isopentenyl-pyrophosphate and lipopolysaccharide antigens.

Dendritic cells and gamma delta T-lymphocytes play a crucial role in the early response to microbial infections. Since both dendritic cells and gamma delta T-lymphocytes may be activated by specific microbial products, we analyzed their interplay in the presence of such respective ligands: lipopolysaccharide and isopentenyl-pyrophosphate. Activated gamma delta T-cells increased the maturational state of dendritic cells induced by lipopolysaccharide, increasing the expression of co-stimulatory and MHC class I and II molecules. IL-12 production by dendritic cells was strongly amplified in the presence of activated gamma delta T-cells and the Th1 polarization of naïve CD4(+) T-lymphocytes was significantly increased. On the other hand, dendritic cells enhanced gamma delta T-cell functions induced by isopentenyl-pyrophosphate and promote their IL-2 independent proliferation through CD86 contact. Altogether, dendritic cells and gamma delta T-cells exert a complementary function promoting an optimal immune response to non peptidic microbial antigens.