title: Characterization and antiviral activity of a newly identified defensin-like peptide, HEdefensin, in the hard tick Haemaphysalis longicornis.
abstract: Tick defensins are antimicrobial peptides that play a major role in the innate immunity of ticks by providing a direct antimicrobial defense. In this study, we identified and characterized a defensin-like encoding gene, HEdefensin, from the expressed sequence tags (EST) database of hemolymph from the hard tick Haemaphysalis longicornis. Expression of the gene in whole adult ticks and in different organs was upregulated during blood feeding, though not after Langat virus (LGTV) challenge. A synthetic HEdefensin peptide demonstrated significant virucidal activity against LGTV but not against an adenovirus in co-incubation virucidal assays. Moreover, the RNAi-mediated gene silencing of HEdefensin did not significantly affect the virus titer as compared to the control group. The data reported here have established the in vitro virucidal activity of the peptide against LGTV. However, its role in the innate antiviral immunity of H. longicornis remains to be explored, and further studies are needed to fully evaluate the potential biological activities of the peptide against bacteria, fungi or parasites.
authors.affiliation: Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan; Department of Clinical and Population Health, College of Veterinary Medicine and Biomedical Sciences, Cavite State University, Cavite 4122, Philippines.
authors.forename: Melbourne Rio
authors.initials: MR
authors.lastname: Talactac
authors.affiliation: Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Yurika
authors.initials: Y
authors.lastname: Yada
authors.affiliation: Laboratory of Public Health, Graduate School of Veterinary Medicine, Hokkaido University, Kita-ku Kita-18 Nishi-9, Sapporo, Hokkaido 060-0818, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yoshii
authors.affiliation: Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan.
authors.forename: Emmanuel Pacia
authors.initials: EP
authors.lastname: Hernandez
authors.affiliation: Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan.
authors.forename: Kodai
authors.initials: K
authors.lastname: Kusakisako
authors.affiliation: Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Maeda
authors.affiliation: Department of Veterinary Paraclinical Sciences, College of Veterinary Medicine, University of the Philippines Los Baños, Los Baños, Laguna 4031, Philippines.
authors.forename: Remil Linggatong
authors.initials: RL
authors.lastname: Galay
authors.affiliation: National Agricultural and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Fujisaki
authors.affiliation: Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Mochizuki
authors.affiliation: Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan. Electronic address: k6199431@kadai.jp.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003264:Containment of Biohazards; D023082:Defensins / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D004669:Encephalitis Viruses, Tick-Borne / Q000276:immunology*; D004675:Encephalitis, Tick-Borne / Q000276:immunology*; D006458:Hemolymph / Q000378:metabolism*; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D026863:Ixodidae / Q000276:immunology*; D016415:Sequence Alignment
chemical_list: D023082:Defensins; D019476:Insect Proteins
keywords: Antimicrobial peptide; HEdefensin; Haemaphysalis longicornis; Langat virus