Mycobacterium tuberculosis Lineage Influences Innate Immune Response and Virulence and Is Associated with Distinct Cell Envelope Lipid Profiles

2011

Mycobacterium tuberculosis Lineage Influences Immune Response and Virulence

Sample size: 18 publication 10 minutes Evidence: moderate

Author Information

Author(s): Krishnan Nitya, Malaga Wladimir, Constant Patricia, Caws Maxine, Thi Hoang Chau Tran, Salmons Jenifer, Thi Ngoc Lan Nguyen, Bang Nguyen Duc, Daffé Mamadou, Young Douglas B., Robertson Brian D., Guilhot Christophe, Thwaites Guy E.

Primary Institution: Centre for Molecular Microbiology and Infection, Imperial College London

Hypothesis

The differences in virulence and immune response among Mycobacterium tuberculosis lineages are induced by lineage-specific variations in cell envelope lipids.

Conclusion

The study found that certain lineages of Mycobacterium tuberculosis are associated with a stronger immune response and higher virulence, particularly in causing disseminated tuberculosis with meningitis.

Supporting Evidence

East Asian/Beijing and Indo-Oceanic strains induced significantly more TNF-α and IL-1β from macrophages than Euro-American strains.
East Asian/Beijing strains were detectable earlier in the blood of infected mice and grew faster in the lungs.
Whole lipid extracts from East Asian/Beijing and Indo-Oceanic strains induced higher concentrations of TNF-α from macrophages than Euro-American lipids.
Mutation of pks15/1 in an Indo-Oceanic strain prevented phenolphthiocerol dimycocerosate synthesis but did not alter macrophage cytokine induction.

Takeaway

Different types of tuberculosis bacteria can make people sicker in different ways, and this study looked at how the bacteria's outer layer affects their ability to cause disease.

Methodology

The study characterized 18 strains of Mycobacterium tuberculosis in macrophages, dendritic cells, and mice to assess their immune response and virulence.