ImmunoTox Letter

December 2023

Report on the 30th Annual Meeting of the Japanese Society ofImmunotoxicology (JSIT2023)

Ryosuke Nakamura
President of the 30th Annual Meeting of the JSIT
National Institute of Health Sciences, JapanThe 30th JSIT Annual Meeting unfolded in Kawasaki, Japan, from September 11 to 13,
2023, at the Tonomachi district of the KING skyfront. Hosted at the Shimadzu Tokyo Innovation
Plaza and the Kawasaki LiSE, supported by Shimadzu Corporation and the city of Kawasaki. On
behalf of the Annual Meeting of the Japanese Society of Immunotoxicology, I would like toexpress our sincere gratitude to them for providing us with such comfortable and relaxing venues.
This year's theme, "New Immunotoxicology Research Required by Society," was chosen
to highlight the growing societal demand for innovative drugs with diverse structures and modesof action, such as mRNA vaccines. These drugs have the potential to revolutionize medicine, butthey also raise new concerns about immunotoxicity. This is a pivotal issue that the JapaneseSociety of Immunotoxicology, a consortium of immunotoxicology experts, aims to address.
Aligned with the theme, Dr. Junichi Koga delivered a special lecture on vaccine
development at SCARDA on Day 1. The symposium "Immunotoxicology in the R&D of New
Modality Drugs and Vaccines" explored challenges and opportunities, featuring insights fromexperts like Dr. Akiko Ishii, Dr. Shogo Matsumura, Dr. Yukari Fujiwara, Dr. Yuko Nagayama, andDr. Yoshimasa Takahashi.
Day 2 shifted focus to methodology. Dr. Kristina E. Howard's insightful online special
lecture on humanized mice models for immunotoxicity assessment sparked lively discussions.
The workshop "Animal Models and the Alternatives Reflect Human Immune Responses: Current
Status and Future Prospects" provided insights from Dr. Shigeki Aoki, Dr. Eita Sasaki, Dr. Takeshi
Watanabe, and Dr. Yasumitsu Nishimura. Professor Riichiro Abe's educational lecture on themechanism of severe drug rash enhanced our understanding of this critical adverse reaction.
The last day's open symposium, "Immunotoxicity Risk Assessment for Chemicals in theEnvironment," underscored the societal importance of environmental chemicals, featuring
perspectives from Dr. Yasunobu Aoki, Dr. Reiko Teshima, Dr. Kiwako Yamamoto, and Dr. EikoKoike.
Marking the 30th anniversary, past presidents Professors Takahiko Yoshida and Kazuichi
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ImmunoTox LetterNakamura delivered a captivating lecture titled "Immunotoxicology: Honor the Past and Build
the Future" on Day 1. Their historical journey, culminating in the field's role in ICH S8 andhighlighting future challenges, resonated deeply, urging us to learn from the past and construct abrighter future for immunotoxicology.
Award lectures by Professor Kazuichi Nakamura and Dr. Toshinobu Kuroishi were held on
the Day 2 afternoon. Drs. Takeshi Susukida and Hideki Hara shared the annual meeting award,tying for first place. Mr. Takayuki Sakai received the best Student and Young Scientist
Presentation Award.
We would like to express our sincere gratitude to all the participants, sponsors, exhibitors,and volunteers for their active discussions and presentations. We are especially grateful for theparticipation of over 160 researchers from all over Japan. Your contributions helped to make thismeeting a truly successful event.
We look forward to seeing you all again at the 31st annual meeting in 2024 in Amagasaki!

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The Best Presentation Award

Glycolysis in CD8+ T cells plays an important role in the onset of HLA-mediatedidiosyncratic drug toxicity

Takeshi Susukida
Graduate School of Medicine and Pharmaceutical Sciences
University of Toyama
I am very honored to receive The Best Presentation Award at the 30th Annual Meeting ofJapanese Society of Immunotoxicology. I would like to sincerely appreciate the support from theselection committee.
This study aimed to examine whether intracellular metabolism change in CD8+ T cell
contributes to the susceptibility to immune-mediated idiosyncratic drug toxicity (IDT), using ourestablished transgenic (Tg) mice carrying chimeric human leukocyte antigen (HLA). Althoughgenome-wide association studies revealed that the occurrence of IDT strongly associates withparticular HLA allotype, it does not occur in all subjects of a given HLA model population,suggesting the difficulties to predict the IDT risk without considering additional factors. Focusing
on HLA-B*57:01 and abacavir (ABC; an anti-HIV drug)-induced immune-mediated IDT (skinrash), we have generated a Tg mouse line carrying HLA-B*57:01 (B*57:01-Tg) and successfully
reproduced abacavir (ABC)-induced skin toxicity with increase of IFN-γ-secreting effector CD8+
T cells (CD44highCD62Llow) and CD8+ T cell dermal infiltration in B*57:01-Tg mice 1-2). Moreover,
we found that serum level of pyruvate, which is a metabolite formed by glycolysis, wassubstantially increased in ABC-treated B*57:01-Tg mice, suggesting the importance of metabolic
regulation for CD8+ T cell immunity in the susceptibility to HLA-mediated ABC-induced IDT. In
this study, we examined whether intracellular metabolism change in CD8+ T cells contributes tothe susceptibility to ABC-induced IDT in the B*57:01-Tg mouse model, by comparing controland calorie restricted (CR) group.
As expected, glycolytic rate in CD8+ T cells was significantly increased by ABC treatment
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ImmunoTox Letterin B*57:01-Tg mice, whereas this tendency was abrogated in the CR diet-fed group. In CR
condition, ABC treatment failed to increase the proportion of effector IFN-γ-secreting CD8+ Tcells, thereby abrogating plasma thymus and activation-regulated chemokine (TARC) levelelevation and CD8+ T cell dermal infiltration (i.e., skin toxicity). Treatment of a glycolysis
inhibitor, 2-Deoxy-D-glucose (2-DG), also attenuated the CD8+ T cell activation and ABCinduced skin toxicity in normal diet-fed B*57:01-Tg mice. These results suggested that glycolysis
in CD8+ T cells may play a major role in the onset of ABC-induced IDT in B*57:01-Tg mice.
This finding lays a foundation to identify unclarified onset risk factors in HLA-related IDT
through further investigation on the molecular regulation of glycolysis. We also believe that ourstudy provides a valuable insight to reduce the IDT onset risk by considering individual
differences in nutritional status in humans.
I would like to express my gratitude to my supervisors; Prof. Yoshihiro Hayakawa (Univ.
of Toyama), Prof. Kousei Ito (Chiba University) and Assoc. Prof. Shigeki Aoki (Chiba Univ.) for
beneficial advisement on this project. I also thank to Dr. Yuchen Sun (National Institute of Health
Sciences) for his valuable technical support on this project.
References：1) Susukida T, Aoki S, Kogo K, Fujimori S, Song B, Liu C, Sekine S, Ito K. Evaluation ofImmune-Mediated Idiosyncratic Drug Toxicity Using Chimeric HLA Transgenic Mice. ArchToxicol. 92(3): 1177-1188, (2018)2) Susukida T, Kuwahara S, Song B, Kazaoka A, Aoki S, Ito K. Regulation of the immunetolerance system determines the susceptibility to HLA-mediated abacavir-induced skin toxicity.
Commun Biol. 4(1): 1137, (2021)

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The Best Presentation Award

Exacerbation mechanism of infectious diseases through inflammasome activation

Hideki Hara
Department of Infectious Diseases, Division of Microbiology and Immunochemistry,
Asahikawa Medical University
It is my great honor to be selected for the 30th Annual Meeting Award of the JapaneseSociety of Immunotoxicology in 2023. I would like to express my sincere gratitude to Dr. Ryosuke
Nakamura, President of the Annual Meeting of the Japanese Society of Immunotoxicology, andother members of the selection committee.
When pathogens such as bacteria infect us, our bodies attempt to eliminate them byactivating innate immunity. Bacterial ligands are recognized through receptors expressing on thecell surface and inside cells. It has been known that some intracellular receptors induce activationof inflammasome, an immune system that induces inflammatory responses. The inflammasome
is an intracellular protein complex composed mainly of intracellular receptors such as Nod-likereceptors and AIM2-like receptors, adapter molecule ASC, and caspase-1 precursor, which
activates caspase-1 to induce maturation and secretion of their substrates, IL-1β and IL-18.
Gasdermin D has also been reported to be a substrate of caspase-1, and it has been shown totrigger pyroptosis, a programmed cell death associated with inflammation. In general, immuneresponses are thought to contribute to host protection, and inflammasomes were previously
reported to be protective in some infectious diseases. However, we have found that when
inflammasome-deficient mice are infected with pathogens such as Listeria monocytogenes andStaphylococcus aureus, the number of bacteria in their organs is lower than that of wild-type miceand they show higher resistance to infection. These results indicate that pathogens exacerbate theinfectious diseases by activating inflammasome responses. We also investigated the mechanismof inflammasome activation in infectious diseases, and found that Listeria delivers bacterial
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double-stranded DNA, a ligand of AIM2, into the cytoplasm, and the inflammasome activation is
promoted by listeriolysin O, the Listeria major virulence factor. More recent studies have revealed
that lipoteichoic acid, a cell wall component, activates NLRP6 inflammasome. Lipoteichoic acids
is widely expressed in Gram-positive bacteria, and we found that activation of the NLRP6inflammasome also exacerbate Staphylococcus aureus infection. Finally, we clarified that
inflammasome-dependent production of IL-18 is detrimental to the host during infection with
Listeria monocytogenes and Staphylococcus aureus. The future progress of research on themechanism by which IL-18 exacerbates infectious diseases and the establishment of noveltreatment for infection targeting IL-18 are highly anticipated. I am looking forward to the 31st
Annual Meeting to be held at Hyogo Medical University where IL-18 was discovered.
References
1. Tanishita Y, Sekiya H, Inohara N, Tsuchiya K, Mitsuyama M, Núñez G, Hara H. Listeria ToxinPromotes Phosphorylation of the Inflammasome Adaptor ASC through Lyn and Syk toExacerbate Pathogen Expansion. Cell Rep. 38, 110414, 2022.
2. Hara H, Seregin SS, Yang D, Fukase K, Chamaillard M, Alnemri ES, Inohara N, Chen GY,Núñez G. The NLRP6 inflammasome recognizes lipoteichoic acid and regulates Gram-positive
pathogen infection. Cell 175, 1651-1664, 2018.
3. Hara H, Tsuchiya K, Kawamura I, Fang R, Hernandez-Cuellar E, Shen Y, Mizuguchi J,Schweighoffer E, Tybulewicz V, Mitsuyama M. Phosphorylation of the adaptor ASC acts as amolecular switch that controls the formation of speck-like aggregates and inflammasome activity.
Nat. Immunol. 14, 1247-1255, 2013.
4. Hara H, Tsuchiya K, Nomura T, Kawamura I, Shoma S, Mitsuyama M. Dependency of caspase1 activation induced in macrophages by Listeria monocytogenes on cytolysin, listeriolysin O,
after evasion from phagosome into the cytoplasm. J. Immunol. 180, 7859-7868, 2008.

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The Student and Young Scientists Award

A CCR4 inhibitor suppresses atopic dermatitis-like skin inflammation byinhibiting the recruitment and expansion of Th2 cells and Th17 cells

Takayuki Sakai
Kindai University Faculty of Pharmacy
I’m deeply honored to receive the Student and Young Scientists Award at the 30th Annual
Meeting of the Japanese Society of Immunotoxicology. I would like to express my sincere
appreciation to the organizing committee and all those who have contributed to this remarkable
event.
My research focused on the role of chemokine receptor CCR4 in atopic dermatitis (AD).
The chemokine receptor CCR4 is a major trafficking receptor expressed by T-helper (Th) 2 cellsand Th17 cells and is considered as a potential therapeutic target for AD. The CCR4 ligand CCL17and CCL22 have been reported to be upregulated in the skin lesions of AD patients. In this study,
we investigated the role of CCR4 in an AD mouse model induced by MC903. Topical applicationof MC903 to ear skin induced increased expression of not only TSLP but also CCL17, CCL22,
IL-4 (Th2 cytokine), and IL-17A (Th17 cytokine). Compound22, a CCR4 inhibitor suppressed
Th2 cells, Th17 cell, and ILC2 which expressed CCR4. We further confirmed that compound22
diminished the expansion of Th2 cells and Th17 cells in the regional lymph nodes. In addition,
compound22 ameliorated AD-like skin lesions. Collectively, CCR4 inhibitors is involved in thepathogenesis of AD by recruitment and expansion of Th2 cells and Th17 cells.
This award is not just a personal achievement but a testament to the collective efforts of
my dedicated team and the invaluable support I have received from mentors and peers.

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The 12th Japanese Society of Immunotoxicology Prize for Encouragement

Preclinical immunotoxicity and immunogenicity studies aimed at improving safety
predictions of biopharmaceuticals

Chiyomi Kubo
on behalf of non-clinical immunosafety researchers
Translational Research Division
CHUGAI PHARMACEUTICAL CO., LTD.
I am deeply honored to have received the 12th Japanese Society of Immunotoxicology Prize
for Encouragement. I would like to express my sincere gratitude to all who nominated me for theaward, to the members of the selection committee, and to all who have enlightened and lead me
over the years. I would like to share the happiness of receiving this award with my colleagues
who have overcome many challenges together.
I started immunotoxicity and immunogenicity research when I joined this pharmaceuticalcompany. In the immunotoxicity research, our purpose is to support non-clinical safetyassessment for effective prediction of toxicity for patients. Firstly, we have prepared several
assays (e.g., T-cell dependent antibody response (TDAR), NK assay, Immunophenotyping) inrodents and monkeys in line with the ICH S8 guideline (Immunotoxicology Studies for
Human Pharmaceuticals) and our drug discovery pipeline. And we also developed human invitro assays such as a cytokine release assay. On the other hand, in the immunogenicity research,
our purpose is to support molecular designs and engineering technologies for the development ofbiotherapeutics with no problematic immunogenicity. Therefore, we developed human in vitro Tcell assays to evaluate the immunogenicity potential, mechanism tools (e.g., MHC-associatedpeptide proteomics (MAPPs), binding/uptake assays, APC functional assays), and deimmunization strategy. We have been assessing discovery candidates and approaching themechanism based de-immunization in all biology projects since a humanized bispecific antibody
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ImmunoTox Letterto coagulation factors IXa and X with a factor VIIIa-cofactor activity, Emicizumab, project.
Lately, we have been addressing analysis of species differences and mechanisms in
immune-related adverse effects of immunotherapy drugs which are often hard to predict in the
animal testing. In addition, we have been analyzing the mechanism of high immunogenic
investigational and marketed drugs and sorting factors that contribute to the immunogenicity.
We will continue this research with changes in line with advances in antibody engineering
technologies, diversification of molecular structures and modes of action, and expansion ofevaluation systems. I would like to make every effort to contribute to the drug safety, theinnovative drug development, and the scientific progress through this research.

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