Migration and maturation of human colonic dendritic cells

Dendritic cells (DC) in the colon may regulate intestinal immunity but rema in poorly characterized. In this study a CD11c(+)HLA-DR(+)lin(-) (CD3(-)CD1 4(-)CD16(-)CD19(-)CD34(-)) population has been identified by, flow cytometr y in cells obtained by rapid collagenase digestion of human colonic and rec tal biopsies. These day 0 (0) CD11c(+)HLA-DR(+)lin(-) cells comprised simil ar to0.6% of the mononuclear cells obtained from the lamina propria, were e ndocytically active, and had the phenotype of immature DC; they were CD40() and expressed low levels of CD83 and CD86, but little or no CD80 or CD25. Similar d0 DC populations were isolated from the colonic mucosa of healthy controls and from both inflamed and noninflamed tissue from patients with Crohn's disease. The lamina propria also contained a population of cells ca pable of migrating out of biopsies during an overnight culture and differen tiating into mature DC with lower levels of endocytic activity and high cel l surface expression of CD40, CD80, CD86, CD83, and CD25. This mature DC po pulation was a potent stimulator of an allogeneic mixed leukocyte (MLR). Ov ernight culture of cells isolated by enzymatic digestion on d0 yielded DC w ith a phenotype intermediate between that of the d0 cells and that of the c ells migrating out overnight. Overnight culture of colonic cells in which D C and HLA-DR(+)lin(+) cells were differentially labeled with FITC-dextran s uggested that some of the maturing DC might differentiate from HLA-DR(+)lin (+) progenitors. This study presents the first analysis of the phenotype, m aturational status, and migratory activity of human gut DC.