Abstract
Neutrophils of the innate immune system are well equipped to kill invading pathogens by generating a variety of reactive oxygen intermediates including singlet oxygen. In his Perspective, [Nathan][1] discusses the surprising finding ([Wentworth][2] et al .) that stalwart members of the acquired immune system, the antibodies produced by B cells, can contribute to this armamentarium by catalytically reacting singlet oxygen with water to produce hydrogen peroxide and a powerful ozone-like oxidant, O3. [1]: http://www.sciencemag.org/cgi/content/full/298/5601/2143 [2]: http://www.sciencemag.org/cgi/content/short/298/5601/2195