Staphylococcus aureus is a common cause of sepsis and toxic shock. These
processes can result in tissue damage and cell death, presumably by
necrosis or apoptosis. Bantel et al. now show that in cultures of Jurkat T
cells, apoptosis can be induced not only by infection with S. aureus itself
but also by S. aureus culture supernatants. The active ingredient in these
supernatants was one of the secreted toxins, a-toxin. Death was not induced
when S. aureus strains lacking the toxin were used nor when antibodies that
could bind a-toxin were added. The mechanism of apoptosis induction appears
to be via the intrinsic death pathway leading directly to cytochrome c
release from mitochondria, rather than via death receptors. Given the
increasing incidence of antibiotic resistance in S. aureus strains, these
findings provide potential leads for therapeutic intervention during staph
infections. -- SMH

J. Cell Biol. 155, 637 (2001).