Whole-genome DNA Microarrays Research Articles

New hopes for anti-bacterial vaccines

As the incidence of antibiotic-resistant strains of bacteria increases, there has been a renewed interest in vaccination as a preventative measure. Historically, however, anti-bacterial vaccines have not always been particularly efficient, as was indeed the case for the Bacille Calmette-Guerin (BCG) vaccine against infection with Mycobacterium tuberculosis. In their paper, Behr et al.1xComparative genomics of BCG vaccines by whole-genome DNA microarray. Behr, M.A. et al. Science. 1999; 284: 1520–1523Crossref | PubMed | Scopus (1054)See all References1 suggest that this might be due to successive gene deletion from the attenuated strain of M. bovis used in the BCG vaccine.The original strain of M. bovis used for the BCG vaccine was lost during World War I, but the authors curated samples of its descendants from around the world. Using gene-array technology and the known genomic sequence of M. tuberculosis, the authors found that 91 open reading frames (ORFs) were missing from virulent M. bovis compared with M. tuberculosis, and that a further 38 ORFs were present in virulent M. bovis but were missing in some or all of the BCG vaccine strains. By comparing the genomic sequences of the vaccine strains, the authors compiled their genealogy. Their data suggest that the inefficacy of some of the modern vaccine strains might be due to the loss of genes that allow their survival in the host with a consequent loss of ability to stimulate a protective immune response. The knowledge gleaned from the sequences should allow a new strain of M. bovis to be generated that can confer immunity with a much higher efficacy.Rather than enhance an old vaccine, McKenney et al.2xBroadly protective vaccine for Staphylococcus aureus based on an in vivo-expressed antigen. McKenney, D. et al. Science. 1999; 284: 1523–1527Crossref | PubMed | Scopus (254)See all References2 have explored ways of making new vaccines, in this case against Staphylococcus aureus, and concentrated on bacterial antigens that were only detected during infection. One such antigen, poly-N-succinyl β-1-6 glucosamine (PNSG), was found to be expressed on the surface of S. aureus isolated from the lung tissue of cystic fibrosis sufferers. Vaccination of mice with this antigen protected mice against kidney disease and death from strains of S. aureus that produced little or no PNSG in vitro. The authors concluded that PNSG might be a vaccine candidate for use in humans.