title: Novel, anionic, antiviral septapeptides from mosquito cells also protect monkey cells against dengue virus.
abstract: We have shown previously that ultrafiltrates (5 kDa cutoff) of cell-free medium from mosquito cell cultures persistently infected with DENV serotype 2 (DENV-2) contained a novel antiviral agent (called viprolaxikine) that could protect pre-treated, naïve mosquito cells from DENV infection. Here, we show that viprolaxikine also reduced DENV-2 titers by almost 4 logs (>99.9%) when compared to Vero cells mock-treated with ultrafiltrates from cultures of uninfected mosquito cells. Protease treatment removed the anti-DENV-2 activity. Pre-incubation for 48-h was required to obtain the maximum, dose-dependent protection against DENV-2, indicating that the antiviral activity was based on the interaction between Vero cells and viprolaxikine rather than direct action of viprolaxikine on DENV-2. Activity was highest against DENV-2, but there was also significant activity against the 3 other DENV serotypes. LC-MS-MS analysis revealed that the active viprolaxikine fraction contained anionic, antiviral peptides, each comprised of 7 amino acids (DDHELQD, DETELQD and DEVMLQD or DEVLMQD) and with a common sequence motif of D-D/E-X-X-X-Q-D. These sequences do not occur in the dengue virus genome, suggesting that the peptides are produced by the host insect cells when persistently infected with DENV-2. These peptides represent a new class of anionic, insect-derived, antiviral peptides with activity against a flavivirus in both mammalian and insect cells.
authors.affiliation: Dept. Biotechnology, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand.
authors.forename: Chaowanee
authors.initials: C
authors.lastname: Laosutthipong
authors.forename: Nipaporn
authors.initials: N
authors.lastname: Kanthong
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Flegel
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D000838:Anions / Q000378:metabolism; D000998:Antiviral Agents / Q000138:chemical synthesis / Q000302:isolation & purification* / Q000494:pharmacology; D002522:Chlorocebus aethiops; D009033:Culicidae / Q000378:metabolism / Q000821:virology*; D016207:Cytokines / Q000302:isolation & purification / Q000494:pharmacology; D003715:Dengue / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D003716:Dengue Virus / Q000187:drug effects* / Q000472:pathogenicity; D004305:Dose-Response Relationship, Drug; D000882:Haplorhini; D054884:Host-Pathogen Interactions; D019476:Insect Proteins / Q000302:isolation & purification / Q000494:pharmacology; D010455:Peptides / Q000138:chemical synthesis / Q000302:isolation & purification* / Q000494:pharmacology; D013997:Time Factors; D014709:Vero Cells; D019562:Viral Load / Q000187:drug effects
chemical_list: D000838:Anions; D000998:Antiviral Agents; D016207:Cytokines; D019476:Insect Proteins; D010455:Peptides