CD8- DCs induce IL-12-independent Th1 differentiation through Delta 4 Notch-like ligand in response to bacterial LPS.

ABSTRACT: Toll-like receptor (TLR) ligation is believed to skew T cell responses toward T helper (Th)1 differentiation by inducing interleukin (IL)-12 secretion by CD8(+) dendritic cells (DCs). However, TLR-dependent Th1 responses occur in the absence of IL-12. To determine how DCs induce Th1 differentiation in the absence of IL-12, we examined the response of IL-12-deficient DCs to bacterial lipopolysaccharide (LPS). We find that LPS activates MyD88-dependent Delta 4 Notch-like ligand expression by CD8(-) DCs, and that these cells direct Th1 differentiation by an IL-12-independent and Notch-dependent mechanism in vitro and in vivo. Thus, activation of the two DC subsets by TLR4 leads to Th1 responses by two distinct MyD88-dependent pathways.

SUBMITTER: Skokos D 

PROVIDER: S-EPMC2118646 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature