We have evaluated the efficacy of antibody-targeted photolysis to kill
bacteria in vivo using specific antibacterial photosensitizer (PS) im
munoconjugates. After infecting the dorsal skin in mice with Pseudomon
os aeruginosa, both specific and nonspecific tin (IV) chlorin e(6)-mon
oclonal antibody conjugates were injected at the infection site. After
a 15 min incubation period, the site was exposed to 630 mm light with
a power density of 100 mW/cm(2) for 1600 seconds. Irradiation resulte
d in a greater than 75% decrease in the number of viable bacteria at s
ites treated with a specific conjugate, whereas normal bacterial growt
h was observed in animals that were untreated or treated with a nonspe
cific conjugate. Antibody-targeted photolysis may be a selective and v
ersatile tool for treating a variety of infections.