Helicobacter pyloriPreferentially Induces Interleukin 12 (IL-12) Rather than IL-6 or IL-10 in Human Dendritic Cells

Abstract

Dendritic cells are potent antigen-presenting cells that are present in the gastrointestinal tract and are required for the induction of a Th1 T-cell acquired immune response. Since infection with the gastric pathogenHelicobacter pylorielicits a Th1 cell response, the interaction of these organisms with dendritic cells should reflect the Th1 bias. We incubatedH. pyloriwith cultured human dendritic cells and measured the cytokine induction profile, comparing the response to that induced bySalmonella entericaserovar Typhimurium. We found thatH. pyloriinduced little interleukin 6 (IL-6) and essentially no IL-10 in contrast toS. enterica.However,H. pyloriinduced levels of IL-12 that were 30% of those induced byS. enterica,indicating a Th1 response. An isogeniccagEmutant ofH. pylorilost about 50% of its IL-12-inducing ability, suggesting a role for thecagtype IV secretion system in the stimulation of dendritic cells.