5-Aminolaevulinic acid and photodynamic therapy reduce HSV-1 replication in HaCat cells through an apoptosis-independent mechanism

Fabrizio Ayala, Elena Grimaldi, Brunella Perfetto, Maria Donnarumma, Anna De Filippis, Giovanna Donnarumma, Maria Antonietta Tufano

Research output: Contribution to journalArticlepeer-review


Background: Photodynamic therapy (PDT) involves the use of a photosensitizing agent, which may require metabolic synthesis (i.e. a prodrug), followed by light activation. Numerous studies have advanced PDT as a means for treating bacteria, fungi and viruses. In this study, the photoinactivation of Herpes simplex virus type 1 (HSV-1) in human keratinocytes using 5-aminolaevulinic acid (5-ALA) was investigated. Methods: HaCat cells were infected with HSV-1 and treated with 5-ALA to verify its antiviral effect during the stages of adsorption and penetration to host cells. Immunoblot analysis was used to estimate the effect of ALA-PDT on the production of viral proteins glycoprotein D (gD), infected cell proteins (ICP) 27 and virion protein (VP) 16. We also investigated whether the effect of ALA-PDT was associated with a cellular apoptotic mechanism through DNA fragmentation and the study of p53, PARP and caspase-3 protein expression. Results: While the treatment of ALA-PDT after the viral adsorption period reduced HSV-1 replication by about 70%, it did not act on the virus in the first phase of infection. The viral proteins' expressions were reduced by ALA-PDT treatments. There was no evidence of ALA-PDT-induced apoptosis. Conclusion: Our data suggest that the target of photoinactivation appears to be viral replication and not a cellular response.

Original languageEnglish
Pages (from-to)237-243
Number of pages7
JournalPhotodermatology Photoimmunology and Photomedicine
Issue number5
Publication statusPublished - 2008


  • 5-aminolaevulinic acid
  • HaCat cells
  • HSV-1
  • Photodynamic therapy

ASJC Scopus subject areas

  • Dermatology
  • Immunology


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