title: Promotion of allergic immune responses by intranasally-administrated nanosilica particles in mice.
abstract: With the increase in use of nanomaterials, there is growing concern regarding their potential health risks. However, few studies have assessed the role of the different physical characteristics of nanomaterials in allergic responses. Here, we examined whether intranasally administered silica particles of various sizes have the capacity to promote allergic immune responses in mice. We used nanosilica particles with diameters of 30 or 70 nm (nSP30 or nSP70, respectively), and conventional micro-sized silica particles with diameters of 300 or 1000 nm (nSP300 or mSP1000, respectively). Mice were intranasally exposed to ovalbumin (OVA) plus each silica particle, and the levels of OVA-specific antibodies (Abs) in the plasma were determined. Intranasal exposure to OVA plus smaller nanosilica particles tended to induce a higher level of OVA-specific immunoglobulin (Ig) E, IgG and IgG1 Abs than did exposure to OVA plus larger silica particles. Splenocytes from mice exposed to OVA plus nSP30 secreted higher levels of Th2-type cytokines than mice exposed to OVA alone. Taken together, these results indicate that nanosilica particles can induce allergen-specific Th2-type allergic immune responses in vivo. This study provides the foundations for the establishment of safe and effective forms of nanosilica particles.
authors.affiliation: Department of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka 565-0871, Japan. yasuo@phs.osaka-u.ac.jp.
authors.forename: Tokuyuki
authors.initials: T
authors.lastname: Yoshida
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: Maho
authors.initials: M
authors.lastname: Fujimura
authors.forename: Kohei
authors.initials: K
authors.lastname: Yamashita
authors.forename: Kazuma
authors.initials: K
authors.lastname: Higashisaka
authors.forename: Yuki
authors.initials: Y
authors.lastname: Morishita
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kayamuro
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nabeshi
authors.forename: Kazuya
authors.initials: K
authors.lastname: Nagano
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Abe
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Kamada
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Tsunoda
authors.forename: Norio
authors.initials: N
authors.lastname: Itoh
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Tsutsumi