RC-2 was active against HSV-1 KOS in cultures and showed protective activity in vivo when used in a prophylactic mode, but the peptide showed limited activity in a postinfection herpes keratitis model. These findings support data obtained from experiments with HIV-1, HSV-2, and influenza A, indicating that RCs inhibit the entry of viruses rather than their replication.

Topical application of MI-S on skin lesions was also not effective, but cutaneously infected mice treated orally with MI-S had significantly reduced disease scores (P < 0.05) after day 9, suggesting that healing was accelerated. Vaginal administration of MI-S 20 min before viral challenge reduced the mean disease scores on days 5 to 9 (P < 0.05), viral titers on day 1 (P < 0.05), and mortality (P < 0.0001) in comparison to the control groups (untreated and vehicle treated). These results show that MI-S may be useful as an oral agent to reduce the severity of HSV cutaneous and mucosal lesions and, more importantly, as a microbicide to block sexual transmission of HSV-2 genital infections.

PURPOSE.To test the in vivo activity of a peptide derived from the protein transducing domain of the human immunodeficiency virus (HIV) Tat protein, TAT-Cd 0 , in a murine herpes simplex type 1 (HSV-1) keratitis model. METHODS.The efficacy of TAT-Cd 0 was assessed in a postinfection treatment model with different concentrations (1 mg/mL, 0.1 mg/mL, 0.01 mg/mL) of the peptide in one of four delivery vehicles: artificial tears, PBS, methylcellulose, and aquaphor cream. Treatment began within 4 or 24 hours postinfection. Viral titers in the tear film were determined by plaque assay. RESULTS. TAT-Cd0 reduced the severity of keratitis in all of the delivery vehicles tested when treatment started, 4 hours postinfection. Peptide in the tears or PBS delivery vehicle had the most significant reduction in disease severity and delayed the onset of vascularization and stromal keratitis. The percentage of mice presenting with disease was also significantly reduced and viral titers were reduced by 1 log at 24 hours postinfection in mice treated with 1 mg/mL TAT-Cd 0 , suggesting that inhibiting replication early is sufficient to achieve clinical effects. Lower concentrations were not effective and delaying treatment by 24 hours was also not effective.CONCLUSIONS. This study shows that TAT-Cd 0 is an effective antiviral against HSV-1 strain KOS when applied shortly postinfection and that aqueous-based formulations are more suitable. (Invest Ophthalmol Vis Sci.