Kendra M Speirs | PubMed Health

PubMed2003

TRAF6 is a critical factor for dendritic cell maturation and development.

IL-1 receptor (IL-1R)/Toll-like receptor (TLR) family and TNF receptor (TNFR) superfamily members are critical for regulating multiple aspects of dendritic cell (DC) biology. Several signaling pathways associated with each family utilize the adapter molecule, TRAF6, but its role in DCs is unclear. By examining TRAF6-deficient mice and bone marrow (BM) chimeras reconstituted with TRAF6-deficient fetal liver cells, we show that proper DC maturation requires TRAF6. In response to either microbial components or CD40L, TRAF6-deficient DCs fail to upregulate surface expression of MHCII and B7.2, or produce inflammatory cytokines. Moreover, LPS-treated TRAF6-deficient DCs do not exhibit an enhanced capacity to stimulate naive T cells. Interestingly, a major population of splenic DCs, the CD4(+)CD8alpha(-) subset, is nearly absent in both TRAF6-deficient mice and BM chimeras. Together these results indicate that TRAF6 regulates the critical processes required for maturation, activation, and development of DCs, the primary cellular bridge between innate and adaptive immunity.

Animals↗

PubMed2002

Differential requirement for NF-kappa B family members in control of helminth infection and intestinal inflammation.

The NF-kappaB family of transcription factors is critical in controlling the expression of a wide range of immune response genes. However, whether individual family members perform specific roles in regulating immunity and inflammation remains unclear. Here we investigated the requirement for NF-kappaB1, NF-kappaB2, and c-Rel in the expression of Th2 cytokine responses, development of host protective immunity, and regulation of intestinal inflammation following infection with the gut-dwelling helminth parasite Trichuris muris. While mice deficient in c-Rel mounted sufficient Th2 responses to expel infection, NF-kappaB1 knockout (KO) and NF-kappaB2 KO mice developed chronic infections associated with elevated production of Ag-specific IFN-gamma. However, only infected NF-kappaB1 KO mice exhibited polarized IFN-gamma responses associated with the loss of intestinal goblet cells and the development of destructive colitis-like pathology. Furthermore, blockade of IL-12 (previously shown to confer resistance in susceptible strains) recovered Ag-specific IL-13 responses and resistance to infection in NF-kappaB2 KO, but not NF-kappaB1 KO mice. Therefore, unique infection, immunological, and pathological outcomes were observed in different NF-kappaB KO strains. Taken together, these results provide direct evidence of nonoverlapping functions for NF-kappaB family members in the development of Th2 cytokine-mediated resistance to T. muris and the control of infection-induced intestinal inflammation.

Animals↗