Research on the effects of chemical substances on children, elderly
people, and those with gene disorders
Title of Research:
15_S03-01-3

Establishment of in vitro evaluation system for the prediction ofrespiratory sensitizing potential of chemicals
Principal Investigator:
Takayuki Yoshimoto, PhD (Professor, Tokyo Medical University, Institute of Medical Science)
6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160-8402, Japan(tel)+81-3-3351-6141 Ext. 431, (e-mail) yoshimot@tokyo-med.ac.jp
Collaborators:
Izuru Mizoguchi, PhD (Research Associate, Tokyo Medical University, Institute of MedicalScience) 6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160-8402, Japan(tel) +81-3-3351-6141 Ext. 448, (e-mail) imizo@tokyo-med.ac.jp
Summary of Research:
Recently, several in vitro assays to predict the respiratory sensitizing potential of chemicals
have been developed, because the use of animal models in safety testing of chemicals issignificantly limited. However, these alternative methods cannot distinguish chemical respiratory
sensitizers and skin sensitizers, although the risk management systems for them are quitedifferent. Therefore, in the present study, we aim at developing a novel in vitro assay, which candiscriminate chemical respiratory sensitizers from skin sensitizers by taking advantage of thefundamental differences between their modes of function; development of helper T (Th) 2 immune
responses, which is critically important for respiratory sensitization.
In this year, we have established an immunocompetent 3D co-culture system of human upper
airway, which consists of human airway epithelial cells, immature dendritic cells (DCs) derived
from human peripheral blood CD14+ monocytes, and human fibroblast cells cultured in individual
scaffolds. Then, these scaffolds were assembled into a 3D multi-cell tissue model, which moreclosely mimics the in vivo situation. Then, three typical chemicals for respiratory and skinsensitizers were added on the 3D co-culture system. The present results indicate that this 3D
co-culture system can predict the respiratory sensitizing potential of chemicals by means ofenhanced expression of key costimulatory molecule OX40L, which is important for Th2
differentiation, as markers in DCs (1). Moreover, to improve the versatility, we have next utilizediPS cell-derived DCs based on published protocols, although this efficacy is not good. Therefore,
we are currently trying to establish a novel method to generate infinitely growing myeloid
progenitors by stimulation with various cytokines and incorporation of genes related to cell cycle
and survival. In addition, we are also trying to develop a novel 3DC/T system, which consists ofsensitized DCs and allogenic naive CD4+ T cells. In this 3DC/T system, IL-4 up-regulation could be
the best marker for the prediction of respiratory sensitizing potential of chemicals.
Timeline:
March 1, 2017-Feberary 28, 2018
Topics:The 5th Annual Meeting of The Japan Chemical Industry Association LRI, poster presentation“Establishment of a novel in vitro evaluation system for the prediction of respiratory sensitizing
potential of chemicals” (The Tokyo Shoken Building, August 25, 2017)
Publications:
1. Mizoguchi I, Ohashi M, Chiba Y, Hasegawa H, Xu M, Owaki T, Yoshimoto T. Prediction ofchemical respiratory and contact sensitizers by OX40L expression in dendritic cellsusing anovel 3D coculture system. Front Immunol. 8, 929, 2017 (IF=6.429).
2. Ohashi M, Mizoguchi I, Chiba Y, Hasegawa H, Xu M, Yoshimoto T. Prediction of chemical
respiratory and contact sensitizers by OX40L expression in dendritic cells using a novel 3D
co-culture system. The 46th Annual Meeting of The Japanese Society for Immunology, oral
poster presentation in English (Sendai, December 12-14, 2017)