Effects of interferon-α on cytopathic changes and titers for feline herpesvirus-1 in primary cultures of feline corneal epithelial cells

Abstract

Objective - To assess the effect of interferon (IFN)-α on viability of feline corneal epithelial cells, replication of feline herpesvirus (FHV)-1, and virus-induced cytopathic changes. Sample Population - Healthy eyes from 10 recently euthanatized cats. Procedure - 4 replicate primary cultures of feline corneal epithelial cells were grown after the addition of 102 to 106 IU of IFN-α/mL. Cultures were examined every 24 hours for evidence of cytotoxic changes. Viable cell counts and percentage of viable cells were determined 48 hours after initiation of culture. In a separate experiment, cultures of corneal cells were inoculated with FHV-1 and cultured for 72 hours with or without 105 IU of IFN-α/mL.The FHV-1-infected cultures were evaluated for viral-induced cytopathic effects, and viral titers were determined in samples of culture supernatant. Results - Interferon-α did not have cytotoxic effects on corneal epithelial cells at concentrations ranging from 102 to 106 IU of IFN-α/mL. Interferon-α at a concentration of 105 IU/mL significantly reduced the cytopathic changes and FHV-1 titers. Conclusions and Clinical Relevance - Lack of in vitro cytotoxic effects and efficacy against FHV-1 infection in primary cultures of feline corneal cells suggests that the in vivo therapeutic effect of IFN-α should be assessed in controlled clinical trials.