Adaptive immune-mediated host resistance to Toxoplasma gondii is governed by the NF-κB regulator Bcl-3 in dendritic cells

Eur J Immunol. 2015 Apr 17. doi: 10.1002/eji.201445045. [Epub ahead of print]

 

Tassi I¹, Claudio E, Wang H, Tang W, Ha HL, Saret S, Sher A, Jankovic D, Siebenlist U.

 

The atypical IκB family member Bcl-3 associates with p50/NF-κB1 or p52/NF-κB2 homodimers in nuclei, thereby either positively or negatively modulating transcription in a context-dependent manner. Previously we reported that Bcl-3 was critical for host resistance to Toxoplasma gondii. Bcl-3-deficient mice succumbed within 3-5 weeks after infection, correlating with an apparently impaired Th1-type adaptive immune response. However in which cell type(s) Bcl-3 functioned to assure resistance remained unknown. We now show that Bcl-3 expression in dendritic cells is required to generate a protective Th1-type immune response and confer resistance to T.gondii. Surprisingly, mice lacking Bcl-3 in dendritic cells were as susceptible as mice globally deficient for Bcl-3. Furthermore, early innate defenses were not compromised by the absence of Bcl-3, as initial production of IL-12 by dendritic cells and IFN-γ by NK cells were preserved. However, subsequent production of IFN-γ by CD4⁺ and CD8⁺ T cells was compromised when dendritic cells lacked Bcl-3, and these mice succumbed at a time when T cell-mediated IFN-γ production was essential for host resistance. These findings demonstrate that Bcl-3 is required in dendritic cells to prime protective T-cell-mediated immunity to T.gondii. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.

KEYWORDS:

Adaptive Immunity, Bcl-3; Dendritic Cells; IFN-γ; T cells; T.gondii

PMID:

25884683

[PubMed - as supplied by publisher]