Chapter 34 - Interaction of dendritic cells with bacteria

Abstract

Dendritic cells (DCs) synthesize a number of cytokines and chemokines after few hours of bacterial infection. The production of both TNFα and IL-6 has been detected in DCs infected with either gram-positive or gram-negative bacteria. Activation of DCs is achieved particularly when bacteria are alive, indeed, heat-inactivated bacteria although phenotypically induce the maturation of DCs, fail to induce a high production of inflammatory cytokines. TNFα production is rapidly induced following infection. It is likely that the phenotypical and functional maturation, which occurs in DCs within 24 h of bacteria uptake, is the result of cytokine amplification during this response. DC activation by TNF-α alone mimics the phenotypical maturation observed after bacterial infection, although the addition of anti-TNF-α antibodies only partly inhibits DC phenotypical and functional maturation. Maturation obtained by whole bacteria is quantitatively and qualitatively more pronounced indicating the induction of several transducing pathways, likely via receptors, which recognize distinct bacterial components.