Tumour necrosis factor and interferon-γ are required in host resistance against virulent Rhodococcus equi infection in mice: cytokine production depends on the virulence levels of R. equi
Version of Record online: 25 DEC 2001
Volume 96, Issue 1, pages 122–127, January 1999
How to Cite
KASUGA-AOKI†, TAKAI, SASAKI, TSUBAKI, MADARAME and NAKANE (1999), Tumour necrosis factor and interferon-γ are required in host resistance against virulent Rhodococcus equi infection in mice: cytokine production depends on the virulence levels of R. equi. Immunology, 96: 122–127. doi: 10.1046/j.1365-2567.1999.00657.x
- Issue online: 25 DEC 2001
- Version of Record online: 25 DEC 2001
Rhodococcus equi is a facultative intracellular bacterial pathogen that causes pneumonia in foals and immunosuppressed humans. There are at least three virulence levels of R. equi and these pathogenicities are associated, in mice, with the presence of virulence plasmids. This study focused on cytokine secretion, in mice, in the course of a primary infection with sublethal doses of R. equi strains of different virulence levels (virulent, intermediately virulent and avirulent). Tumour necrosis factor (TNF) and interferon-γ (IFN-γ), but not interleukin-4 (IL-4) and interleukin-10 (IL-10), were induced endogenously in mice in relation to the multiplication and clearance of virulent and intermediately virulent strains of R. equi. These cytokines were not detected in mice infected with avirulent R. equi. Deaths occurred among mice treated with monoclonal antibodies (mAbs) against either TNF or IFN-γ prior to sublethal dose infection with virulent and intermediately virulent strains of R. equi, but not with avirulent R. equi. These results suggested that cytokine production depended largely on the virulence levels of R. equi: TNF and IFN-γ were required early during infection with virulent R. equi to limit replication and clearance of bacteria within the organs, but they were not necessary for limiting infection with avirulent R. equi.