17 June 1998
TB Bacillus Stands Revealed
We know the killer's social background - and now we have its genetic fingerprint. Six years of research has come good in revealing the blueprint of the TB bacterium, first isolated over a century ago when tuberculosis was more coyly called consumption.
Once linked with languishing and lasciviousness, TB has long lost its "romantic" image as the disease of the pale and interesting. It kills three million a year, and has made a far from glamorous comeback in countries like Britain, as the bacillus homes in on the homeless and poorly housed. The latest work on its genetic make-up should help devise medical ways to combat it, by improved preventive vaccination and treatment.
The decoding of the complete genome sequence, by Stewart Cole's team at the Pasteur Institute in Paris and Bert Barell at the Sanger Centre in Cambridge, England, reveals the functions of the 4 000 genes in mycobacterium tuberculosis. The results are published in the June 11 issue of Nature.
Many of its genes are apparently devoted to producing enzymes which enable it to get energy from the fat in infected body cells. Its cell wall acts as a barrier to a large number of antibiotics, but the detailed genetic information about its structure and resistance mechanisms should help develop ways to combat the disease. Of particular assistance may be the discovery of the unexpected presence of two families of glycine-rich proteins, codenamed PE and PPE.
For researchers, the challenge now is to use this information to create more effective anti-TB drugs and identify antigens which could be used in a vaccine.