CAP37-Derived Antimicrobial Peptides Have In Vitro Antiviral Activity against Adenovirus and Herpes Simplex Virus Type 1

Purpose: The antiviral activity of an established antibacterial CAP37 domain and its extracellular mechanism of action were investigated. Methods: CAP37-derived peptides modified to assess the importance of disulfide bonds were evaluated in cytotoxicity and antiviral assays (direct time kill, dose dependency, and TOTO-1) for adenovirus (Ad) and herpes simplex virus type 1 (HSV-1). Results: Variable virus, adenovirus serotype-dependent, and dose-dependent inhibition were demonstrated without cytotoxicity. For peptide A (CAP3720-44), TOTO-1 dye uptake was demonstrated for Ad5 and HSV-1. Conclusions: Unlike the antibacterial activity of this CAP37 domain, its antiviral activity is not fully dependent upon disulfide bond formation. Viral inhibition appears to result, in part, from disruption of the envelope and/or capsid.