title: Characterization of chikungunya virus infection of a human keratinocyte cell line: role of mosquito salivary gland protein in suppressing the host immune response.
abstract: The chikungunya virus (CHIKV) is a mosquito-borne virus that has recently re-emerged in several countries. On infection, the first vertebrate cells to come into contact with CHIKV are skin cells; mosquitoes inoculate the virus together with salivary gland protein into host skin while probing and feeding on blood. However, there is little known about the susceptibility of human skin cells to CHIKV infection. To clarify this, we investigated the kinetics of CHIKV in the human keratinocyte cell line, HaCaT. CHIKV actively replicated in HaCaT cells, with virus titers in the supernatant increasing to 2.8 × 10(4) plaque-forming units (PFU) ml(-1) 24h post infection. CHIKV infection suppressed production of interleukin-8 (IL-8) in HaCaT cells. The function of IL-8 is to recruit immune cells to virus-infected sites, a process known as chemotaxis. Furthermore, we assessed the role of mosquito salivary gland protein in CHIKV infections by comparing the levels of CHIKV gene expression and chemokine production in HaCaT cells with and without salivary gland extract (SGE). SGE enhanced both the expression of the CHIKV gene and the suppression effect of CHIKV on IL-8 production. Our data suggest that the HaCaT cell line represents an effective tool for investigating the mechanism of CHIKV transmission and spread in skin cells. At the mosquito bite site, CHIKV works together with SGE to ensure the virus replicates in skin cells and escapes the host immune system by suppression of IL-8 production.
authors.affiliation: Mahidol-Osaka Center for Infectious Diseases, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand.
authors.forename: Orapim
authors.initials: O
authors.lastname: Puiprom
authors.forename: Ronald Enrique
authors.initials: RE
authors.lastname: Morales Vargas
authors.forename: Rutcharin
authors.initials: R
authors.lastname: Potiwat
authors.forename: Panjaporn
authors.initials: P
authors.lastname: Chaichana
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Ikuta
authors.forename: Pongrama
authors.initials: P
authors.lastname: Ramasoota
authors.forename: Tamaki
authors.initials: T
authors.lastname: Okabayashi
mesh_terms: D018354:Alphavirus Infections / Q000276:immunology / Q000635:transmission / Q000821:virology; D000818:Animals; D045744:Cell Line, Tumor; D018925:Chemokines / Q000096:biosynthesis; D065632:Chikungunya Fever; D002646:Chikungunya virus / Q000502:physiology*; D002522:Chlorocebus aethiops; D009033:Culicidae / Q000378:metabolism / Q000821:virology; D006367:HeLa Cells; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000821:virology*; D012469:Salivary Glands / Q000378:metabolism; D014709:Vero Cells; D014779:Virus Replication
chemical_list: D018925:Chemokines