Research Reveals How TB Evades The Immune System

Researchers now have greater insight into the biological mechanisms of tuberculosis (TB) and how the pathogen is able to evade the immune system, after conducting the largest study of genetic susceptibility to the disease.

In order to further explore how a person’s DNA affects their risk of contracting TB and their risk of latent TB converting to active TB, researchers conducted a genome-wide association study comparing the genomes of 5500 TB patients and 5600 individuals without TB.^{1,2
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In an analysis of 7.6 million genetic variations, researchers identified variants in DNA sequences for the gene ASAP1 on chromosome 8 which seemed to impact a person’s susceptibility to TB. ¹ The gene is responsible for encoding proteins found in a large number of immune cells known as dendritic cells, which help to activate immune response to pathogens.

These variations inhibited the movement of dendritic cells, explaining the previously-observed slow movement of dendritic cells infected with M. tuberculosis, which in turn may allow the pathogen to evade the immune system. ^1,2

“TB is a major global health problem and the threat of drug-resistance means that we urgently need to develop new ways of fighting back,” they concluded.

“In future [sic], it may be possible to target immune pathways that involve ASAP1 to design efficient vaccines for TB prevention.”

-Michelle Canales Butcher

References:

1. The University of Cambridge. Gene discovery provides clues to how TB may evade the immune system. March 16, 2015. www.cam.ac.uk/research/news/gene-discovery-provides-clues-to-how-tb-may-evade-the-immune-system. Accessed March 18, 2015.

2. Curtis J, Luo Y, Zenner HL, et al. Susceptibility to tuberculosis is associated with variants in the ASAP1 gene encoding a regulator of dendritic cell migration. Nature Genetics. 2015 March [epub ahead of print] doi: 10.1038/ng.3248.