Abstract
Purpose:
To evaluate the effectiveness of photodynamic antimicrobial chemotherapy (PACT) against herpes simplex virus-type 1 (HSV-1).
Methods:
PACT with a porphyrin derivative (TONS504; Porphyrin Lab, Okayama, Japan) and a light-emitting diode (LED) device (CCS, Kyoto, Japan) that delivers light at a single wavelength (660 nm) was applied to coverslips containing confluent FL cells in the presence of HSV-1 at a multiplicity of infection of 0.01 virus per cell. The cells included infected with HSV-1 were exposed to TONS504 at concentrations of 0.01 to 10 µg/mL, irradiated at light energies of 10, 20, or 30 J/cm2, and cultured at 37°C under 5% CO2 for 24 h. The effectiveness of TONS504-PACT against HSV-1 was then evaluated by immunofluorescence staining of the cells with rabbit polyclonal antibodies to HSV-1. Cell nuclei were also stained with 4′, 6-diamidino-2-phenylindole for evaluation of cell viability.
Results:
TONS504-PACT inhibited HSV-1 activity in the infected cells in a manner dependent on both TONS504 concentration and light energy. Inhibition was apparent at a TONS504 concentration of 10 µg/mL with a light energy of 10 J/cm2, and at 1 to 10 µg/mL with a light energy of 20 or 30 J/cm2. TONS504 did not inhibit HSV-1 activity in the infected cells at any of the concentrations tested in the absence of light exposure. TONS504-PACT had no apparent effect on the viability of FL cells.
Conclusions:
TONS504-PACT had a virucidal effect on HSV-1 in vitro without any apparently harmful effect on host cells.
Keywords: 480 cornea: basic science •
422 antibiotics/antifungals/antiparasitics •
647 photodynamic therapy