Genes of leukaemia virus less essential than assumed

19 Jul 2019 | Back to News, Publications and Annual Reports

When you’re ill, you go to see a doctor. Sometimes the doctor needs to send your blood to a specialist laboratory. If you’re a sick monkey in a European zoo, then there’s a strong chance that the vet will send your blood to BPRC for analysis. 

In fact, as a scientific institute BPRC makes a major contribution to the health of monkeys in zoos and animal shelters. Every year we carry out around 50,000 (!) diagnostic tests for vets who practise elsewhere. And sometimes the things we find are so interesting that this leads to follow-up research. Such as the blood from a sick bonnet macaque, or zati, recently sent to us by the vet of an animal shelter.

Increased chance of leukaemia

Our tests showed that the animal was infected with the simian T-cell leukaemia virus, also known as STLV. This virus is closely related to HTLV (human T-cell leukaemia virus), which in turn is a little brother of the well-known HIV. All these interrelationships are no coincidence, because in the distant past these viruses had the same ancestor which affected a range of primates. 

Genetic analysis has shown that at various times in the past these viruses made the jump from primates to humans. HIV is known to cause AIDS in humans, and we also know that people who carry HTLV have a higher chance of contracting leukaemia.

Different than expected

STLV has previously been found in other macaques and in gorillas, but never before in a bonnet macaque. As such, this required closer investigation. Researchers at BPRC first unravelled the genetic code of the virus, which revealed that the virus was lacking certain genes. Genes which were previously thought to be essential for the virus. 

This led to the next question: whether these genes are only lacking in the virus found in bonnet macaques. In order to answer this, we compared the genetic code of this virus with that of other HTLV and STLV variants. And we discovered that in fact these genes are often lacking. Which means that these genes are not absolutely essential for the development of leukaemia. 

New light on the issue

This is a discovery that’s not only hugely interesting for virologists, but which above all casts new light on HTLV. In the future, this information may help researchers to better understand the role played by HTLV in the emergence of leukaemia in patients, and thus help them to develop better treatment methods for leukaemia. 

Would you like to know more about this fascinating area of research? Then you can find the full article on the website of PLOS neglected tropical diseases