M. tuberculosis is the talk of the day – Two separate studies help us understand this notorious organism better

Two separate studies could prove very beneficial in treating tuberculosis (TB). The first study is on the Mycobacterium tuberculosis (MTB) proteome microarray which gives an overview of global protein function and immunogenicity in the bacteria. Until now, poor understanding about the basic biology of this notorious bacterium has hampered the development of diagnostic tests, drugs and vaccines. Hence researchers present a functional MTB proteome microarray covering most of the proteome. They identified 59 PknG-interacting proteins, 30 bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) binding proteins, and 14 MTB proteins that help differentiate between TB patients with active disease and recovered individuals. Results suggest that the MTB rhamnose pathway is likely regulated by both the serine/threonine kinase PknG and c-di-GMP.

Another study published recently talks about a cytokine and chemokine mRNA assay to efficiently diagnose MTB infection status. Presently, Interferon γ (IFNγ) release assay have limited sensitivity as they cannot distinguish active TB disease and latent TB infection. Hence researchers have come up with a combination of cytokine and IFN-γ–induced chemokine mRNA assay which can be performed on whole blood. A real-time RT-PCR TaqMan assay for targeting levels of 8 human targets included IFN-γ, tumor necrosis factor (TNF)-α, IL-2R, IL-4, IL-10, CXCL9, CXCL10, and CXCL11. The assay has been evaluated in three different study groups. Results revealed that the sensitivity of TNF-α, IL-2R, and CXCL10 in the active pulmonary TB (PTB) group was high while their sensitivity was lesser in the latent TB infection (LTBI) group.  Statistical results showed that TNF-α and CXCL9 were the best individual markers for differentiating between the PTB, LTBI, and non-TB groups. The combination of IFN-γ, TNF-α, and IL-2R, and the combination of TNF-α, IL-2R, CXCL9, and CXCL10 showed the best performance for detecting active PTB (both 100% positivity) and LTBI.

Both these studies will prove to be extremely beneficial to diagnose and treat tuberculosis.

The original publications can be accessed at: http://www.cell.com/cell-reports/abstract/S2211-1247%2814%2900989-9 and http://jmd.amjpathol.org/article/S1525-1578(14)00201-3/abstract

Disclaimer: This article does not reflect any personal views of the authors/editors.

Categories: Research

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