Repository logo
 

Mice Deficient in T-bet Form Inducible NO Synthase-Positive Granulomas That Fail to Constrain Salmonella.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Perez-Toledo, Marisol  ORCID logo  https://orcid.org/0000-0002-5734-255X
Beristain-Covarrubias, Nonantzin  ORCID logo  https://orcid.org/0000-0002-4828-5282
Channell, William M 
Hitchcock, Jessica R 
Cook, Charlotte N 

Abstract

Clearance of intracellular infections caused by Salmonella Typhimurium (STm) requires IFN-γ and the Th1-associated transcription factor T-bet. Nevertheless, whereas IFN-γ-/- mice succumb rapidly to STm infections, T-bet-/- mice do not. In this study, we assess the anatomy of immune responses and the relationship with bacterial localization in the spleens and livers of STm-infected IFN-γ-/- and T-bet-/- mice. In IFN-γ-/- mice, there is deficient granuloma formation and inducible NO synthase (iNOS) induction, increased dissemination of bacteria throughout the organs, and rapid death. The provision of a source of IFN-γ reverses this, coincident with subsequent granuloma formation and substantially extends survival when compared with mice deficient in all sources of IFN-γ. T-bet-/- mice induce significant levels of IFN-γ- after challenge. Moreover, T-bet-/- mice have augmented IL-17 and neutrophil numbers, and neutralizing IL-17 reduces the neutrophilia but does not affect numbers of bacteria detected. Surprisingly, T-bet-/- mice exhibit surprisingly wild-type-like immune cell organization postinfection, including extensive iNOS+ granuloma formation. In wild-type mice, most bacteria are within iNOS+ granulomas, but in T-bet-/- mice, most bacteria are outside these sites. Therefore, Th1 cells act to restrict bacteria within IFN-γ-dependent iNOS+ granulomas and prevent dissemination.

Description

Keywords

Animals, Granuloma, Interferon-gamma, Interleukin-17, Mice, Mice, Knockout, Nitric Oxide Synthase Type II, Salmonella Infections, Salmonella typhimurium, T-Box Domain Proteins, Th1 Cells

Journal Title

J Immunol

Conference Name

Journal ISSN

0022-1767
1550-6606

Volume Title

205

Publisher

The American Association of Immunologists