TB or not TB?

Justin Williams ’13

Ever since doctor Robert Koch discovered the bacteria responsible for tuberculous, there has been many hours poured into researching everything about the disease. Through the years, researchers have unearthed almost everything, but one area that is notably lacking is determining any kinds or risk factors. However, on March 4, 2010, researchers at the University of Washington have discovered a gene that may be a major determining factor in susceptibility to TB.

Researchers conducted experiments on zebrafish, in which the severity of the TB could be easily identified due to their clear bodies. The scientists genetically altered the genetic makeup of the zebrafish before injecting them with the tuberculous bacteria and then observing the severity of their TB symptoms.

Their experimentation and subsequent results turned out to be very interesting. They found that the lta4h gene, and it’s genotype (what two particular copies of it you have) are very important in determining how susceptible a person is to contracting TB.

For those of you who are not familiar with genetics, the majority of genes come in two differentforms. You get one copy from each of your  parents. It is possible to get both of one kind, one of each, or one of  the other kind. In this particular lta4h gene, the two different types  are inflammatory and anti-inflammatory. Researchers found that  when zebrafish have one copy of each of the genes, their response to  TB is much better than if they only have copies of one or the other  (i.e. the response of zebrafish with one inflammatory and one anti-inflammatory copy was much better than those who had two copies of the inflammatory or two copies of the anti-inflammatory).

While this research was conducted on zebrafish, the scientists did look into the structure of the gene in humans to determine its relevance. Their investigations proved fruitful and the implications of this for humans are promising.Also, their newfound knowledge that an over inflammatory response can be hurtful for the fight against TB provides some hope “that corticosteroids and other anti-inflammatory agents can be useful as adjuvants in some cases of TB where antibiotics alone are failing.” Whichever way you look at it, the results are exciting and promising for people involved with tuberculous.

Sources:

http://www.eurekalert.org/pub_releases/2010-03/uow-rdg030210.php

http://nobelprize.org/educational_games/medicine/tuberculosis/readmore.html