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Updated: May 7, 2026

Whole-animal Imaging and Flow Cytometric Techniques for Analysis of Antigen-specific CD8+ T Cell Responses after Nanoparticle Vaccination
Published on: April 29, 2015
Biodistribution of vaccines comprised of hydrophobically-modified poly(γ-glutamic acid) nanoparticles and antigen
Riki Toita1, Kenshi Nakao, Atsushi Mahara
1Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, Japan.
Abstract:
Fluorophores-modified nanoparticles comprised of poly(γ-glutamic acid)-phenylalanine (γ-PGA-Phe-633) and ovalbumin (OVA-750) termed NPs-633/OVA-750 were prepared to assess their biodistribution using an in vivo fluorescence imager. Dynamic light scattering measurements indicated that NPs-633/OVA-750 were about 200nm in diameter. The release of encapsulated OVA from NPs-633 in PBS was negligible (∼10%) for a week. When subcutaneously injected, the localization period of OVA-750-encapsulated into NPs-633 at the site of injection (SOI) was much longer than that of free OVA-750, but was shorter as compared to a mixture with aluminum hydroxide. The NPs-633 disappeared at the SOI and major organs within 1month after administration. Moreover, intravenously and intraperitoneally administered NPs-633 were mainly observed at the liver, and there was more rapid clearance from all organs as compared with non-biodegradable NPs. These fast clearance and degradation characteristics of γ-PGA-Phe NPs will be important not only for avoiding undesired adverse effects, but also for inducing a strong vaccine effect.

