Culture of bone marrow cells in GM-CSF plus high doses of lipopolysaccharide generates exclusively immature dendritic cells which induce alloantigen-specific CD4 T cell anergy in vitro

Dendritic cells (DC) can be generated from mouse bone marrow (BM) in the pr esence of granulocyte-macrophage colony-stimulating factor (GM-CSF). Bacter ial stimuli such as endotoxin/lipopolysaccharide (LPS) can induce their fin al maturation. When BM-DC cultures were treated at day 6 or later with LPS, this final maturation was induced in vitro within 24 h. Such mature DC exh ibited high levels of surface MHC II molecules and potent T cell sensitizin g, but reduced endocytosis capacity. In contrast, immature DC express only few MHC II molecules and are weak T cell stimulators but highly endocytic. When BM-DC cultures in GM-CSF were treated with 1 mu g/ml LPS at day 0 of t he culture or throughout the culture, only immature DC developed as defined by phenotype (MHC II low) and function (high endocytosis, weak primary mix ed lymphocyte reaction). Those early LPS-treated immature DC induced alloan tigen-specific anergy of CD4(+) T cells in vitro. These findings might cont ribute to the understanding of reduced T cell immunity in the course of sep tic shock and find application in DC-mediated tolerogenic immunotherapy str ategies.