Re: IBD & Dioxins Link?

[TCDD suppresses tumor necrosis factor-alpha and anti-CD40-induced
activation of NF-kappaB/Rel in dendritic cells: p50 homodimer
activation is not affected]
TCDD suppresses many immune responses, both innate and adaptive.
Suppression is mediated by the aryl hydrocarbon receptor (AhR), a
ligand-activated transcription factor. The AhR mediates TCDD toxicity
presumably through the alteration of transcriptional events, either by
promoting gene expression or potentially by physically interacting
with other transcription factors. Another transcription factor, NF-
kappaB/Rel, is involved in several signaling pathways in immune cells
and is crucial for generating effective immune responses. Dendritic
cells (DCs), considered to be the "pacemakers" of the immune system,
were recently recognized as targets of TCDD and are also dependent on
NF-kappaB/Rel for activation and survival. In these studies, we
investigated whether TCDD would alter the activation of NF-kappaB/Rel
in DCs ... These results suggest that TCDD may alter the balance ...
in DCs, leading to defects in the DCs and suppression of the immune
response. PMID: 12181450