Taming a Worldwide Killer
the deciphering three years ago of the complete genome of the bacterium
responsible for TB in humans, the way became open to discovering how the disease
is caused in humans and domestic animals.
Leicester research team, led by Dr Mark Carr of the Department of Biochemistry,
is investigating a family of proteins (molecular machines) which are associated
with the ability of the TB bacterium to infect people and also with the
development of immunity to the disease.
Carr explained: “ Currently, there are about a dozen or so proteins from the
TB bacterium where there is some clear link with immunity or infection.
What we have done is focus on a few of these proteins to try to
understand what they do and how they do it, which will allow us to take a more
informed approach to new vaccine development and the selection of targets for
new TB drugs.”
Dr Carr has no illusions about the importance of his research. Tuberculosis is a major infectious disease amongst humans, responsible for the deaths of about 3 million people annually, and is a growing world-wide problem. Nor is it confined to the developing world, with drug resistant strains of the TB bacterium becoming an increasing problem in both Western Europe and North America.
He added: “If you walk around the streets of central London or New York you will probably be exposed to someone with active TB. Also, many people do not realise that TB has little respect for social standing or background, and in recent years in New York it has affected both Wall Street executives and people living on the streets.”
“TB is also closely linked to AIDS. If you have a depressed immune system the TB bacterium will readily take advantage, which is why it has re-emerged in Africa so strongly.”
is, however, optimistic in the long term. “Within
ten years we should have a more effective vaccine for TB, which represents the
best hope for clearing the disease from the third world.”
Wellcome Trust funding is the second grant the Leicester group has received from
the Trust for this research. In addition it has received funding for students to
work on the project from the BBSRC and Central Veterinary Laboratories. The
project is a collaboration with Dr Richard Williamson at the University of Kent
and with the TB Research Group at the Central Veterinary Laboratories (Dr Glyn
Hewinson and Dr Stephen Gordon).
The bacterium responsible
for the disease in humans is Mycobacterium tuberculosis, which was one of the first organisms to
have its complete instructions for life (genes) decoded. TB in cattle is caused
by Mycobacterium bovis.
The two bacteria are very closely related and it is now believed that
humans were responsible for passing the disease to cattle rather than visa
A major challenge for
current and future scientific research in tuberculosis is to identify which of
the almost 4000 sets of genes carried by M.
tuberculosis are required for the bacteria to infect humans, and to
understand what the proteins produced by these genes are doing and how. In the
long term, this type of research will lead to the development of improved
tuberculosis therapies and vaccines.
The Leicester research
project supported by the Wellcome Trust is focused on a family of molecular
machines (the ESAT-6/CFP-10 protein family), which appear to play a key role in
the infection process and in the development of protective immunity.
The currently available
vaccine (BCG) uses a weakened strain of M.
bovis to induce immunity. It is about
80% effective for people of Western European descent, but in the Indian
subcontinent it offers virtually no protection at all, for reasons which are not
One third of the
world’s population carries the TB bacterium, but only a small percent develop
tuberculosis is fairly
closely related to the bacterium responsible for leprosy (Mycobacterium
leprae) and so knowledge gained from biochemical studies of TB may well
benefit the fight against leprosy.
The Central Veterinary
Laboratories are part of DEFRA.
to editors: Further information is
available from Dr Mark Carr, Department of Biochemistry, University of
Leicester, telephone 0116 252 3054, email email@example.com
This document has been approved by the head of department or section.