【Member Introduciton#6】Dr. Yasuyuki Goto (Professor, Department of Animal Resoucrce Sciences, Graduate School of Agricultural and Life Sciences / Faculty of Agriculture, The University of Tokyo)

Connections Formed Through Leishmania

Osawa:
Could you tell us about the work you’re currently doing?

Goto:
Our lab is called the Laboratory of Applied Immunology, and we focus on research in infection and immunity. Our main topic is an infectious disease caused by a parasite called Leishmania. The lab itself has been around for about 30 years, and I’m the third professor to head it. The founding professor, Dr. Onodera*, was involved in research on prion diseases and slow virus infections. The second professor was my direct mentor, Dr. Matsumoto*, who was an associate professor at the time I joined the lab and had already started working on Leishmania. Although most students in the lab were doing prion research, I chose to work with Dr. Matsumoto and have been consistently researching Leishmania ever since.

These days, we cover everything related to Leishmania—from basic immunology to the clinical aspects of the disease and potential countermeasures. So when people ask me what I do, it’s hard to answer in any other way than simply saying, “I work on Leishmania.” Our lab takes a comprehensive approach from basic to applied research. For example, Dr. Sanjoba* works on vector insects. In essence, our lab divides up different areas of study that all contribute toward controlling Leishmania.

*Dr. Onodera: Dr. Takashi Onodera, Professor Emeritus, Center for Food Safety Research, Graduate School of Agricultural and Life Sciences, The University of Tokyo
*Dr. Matsumoto: Dr. Yoshitsugu Matsumoto, Professor Emeritus, Graduate School of Agricultural and Life Sciences, The University of Tokyo
*Dr. Sanjoba: Dr. Chizu Sanjoba, Associate Professor, Department of Animal Resoucrce Sciences, Graduate School of Agricultural and Life Sciences / Faculty of Agriculture, The University of Tokyo

Osawa:
What led you to your current line of work?

Goto:
As I mentioned earlier, my path hasn’t changed much. I’ve always stayed in the field of Leishmania. I had the opportunity to study abroad in the U.S. as a postdoc under the guidance of Dr. Aikawa*, and later I moved to Obihiro University of Agriculture and Veterinary Medicine. The locations have changed, but my focus on Leishmania research has remained constant. In my fifth year as a postdoc in the U.S., I started wanting to return to Japan, and I was fortunate to be accepted at Obihiro University. I’ve really been able to survive this far thanks to the many people I’ve been lucky to meet and work with. (laughs)

*Dr. Aikawa: Dr. Masamichi Aikawa (formerly of the University of Tokyo)

Osawa:
Were you already doing similar immunology research during your master’s program?

Goto:
Yes, I was. The research theme I was given during my master’s course was on developing a live vaccine for Leishmania. We thought that if we could create a strain of Leishmania that expresses cytokines like interferon-gamma, it might function as a live vaccine upon infection. So, I was trying to engineer Leishmania to express various cytokines. Initially, things weren’t going well, especially with the expression vectors. But once I received an expression vector from another mentor of mine, Dr. Kawazu*, things started to work.

*Dr. Kawazu: Dr. Shin-Ichiro Kawazu, Professor of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine

Leishmania is Fascinating!

Osawa:
What do you find interesting or rewarding about your current work?

Goto:
Well, it’s not just that I find Leishmania cute! (laughs) Leishmania is biologically unique and immunologically fascinating. Many people who study Leishmania are drawn to it because of its intriguing nature—and I’m one of them. The field itself is quite niche, and many researchers in this area are truly Leishmania-focused, to the extent that the word “Leishmaniac” is used to describe them.
There’s even a conference held every four years dedicated solely to Leishmania. Everyone there is intensely focused on this parasite, to the point that someone from outside the field might find it difficult to follow the discussions.

Osawa:
That sounds like a very interesting conference!

Goto:
Yes, in terms of research interest, Leishmania is fascinating both as a living organism and from an immunological perspective.
By the way, have you ever thought about why you’re interested in diseases?

Osawa:
I guess it’s because diseases can dramatically change people’s lives, and as long as we live, we have to keep dealing with them.

Goto:
Exactly. From a public health standpoint, controlling infectious diseases is extremely important. But we’re also interested in the fundamental question: why do we get sick in the first place?
When a pathogen enters the body, it can cause illness. But even when the immune system is working properly, the resulting immune response can sometimes be the very cause of disease. Take fever or sneezing, for example. Are you allergic to pollen?

Osawa:
Yes, I’m suffering from hay fever right now.

Goto:
Me too. But people without an immune response to pollen don’t get hay fever, right? So while the immune system protects us, it can also cause harm. That contradiction fascinates me. Maybe pathogens aren’t always the sole culprits—we should consider the role of the immune system itself. If we can better balance the immune response, perhaps we can resolve diseases without having to eliminate the pathogens entirely.

Osawa:
That’s a very interesting perspective.

Goto:
In that sense, parasitic infections are particularly compelling from an immunological and disease mechanism perspective. Fast-growing pathogens often create straightforward “fight or die” situations, but chronic infections like those caused by parasites are much more complex. These pathogens are pros in their own right, and immune balance becomes key. I’ve always been interested in diseases since childhood, and I now find parasites to be the most fascinating of all.

Osawa:
On the flip side, what challenges or difficulties have you encountered in researching Leishmania?

Goto:
Earlier I mentioned the interest in chronic parasitic infections and immune response—but the flip side is that experiments take an incredibly long time. For example, in malaria, a short-term model may yield results in about a week, and even in primate models, immunological differences show within a month.
In contrast, for our visceral leishmaniasis mouse model, one infection experiment takes around six months. Since we need to observe long-term symptoms, we spend a lot of time just waiting. This makes experimental turnover very slow, which is one of the biggest challenges.
Vaccine development studies in the U.S. are also conducted on a yearly basis. If you want to try a new vaccine formulation and redo the experiment, that can easily become a 2–3 year project. That’s a common limitation in research on chronic parasitic infections.

From Japan to the World

Osawa:
What do you think is the significance of Japan or Japanese researchers contributing to tropical medicine?

Goto:
To be honest, it’s difficult for Japanese researchers to lead Leishmania control efforts abroad because research on Leishmania is already very active in other countries. There’s no strong demand for a specifically “Japanese” role in this area.
For example, with schistosomiasis japonica, Japan has a unique track record of successfully eliminating the disease. That kind of expertise can be directly transferred to island nations like Indonesia or the Philippines. But for Leishmania, Japan doesn’t have a comparative advantage or extensive know-how.
So, while we may compete fairly in basic research, we don’t have a particular strength when it comes to public health applications in tropical medicine.

Osawa:
I see.

Goto:
Dr. Sanjoba has some advantage in her work on vector insects, and I might have some strength in diagnostics. If we have a specific expertise, we can contribute at the global level. But honestly, I don’t think we can say that Japanese researchers inherently have a unique role in tropical medicine just because they’re Japanese.

Osawa:
That’s a very thought-provoking point. As a student, I’ve also wondered if there’s something we can do “because we’re Japanese,” but now I realize that unless we have a specific strength, we may not be able to contribute meaningfully.

Goto:
Have you ever been abroad? I recently visited Zambia and Malawi. These countries don’t see a lot of foreign researchers regardless of nationality. So it’s not about being Japanese—it’s more about whether someone has the capacity and knowledge to help.

I’m currently working on an AMED* project in Zambia and Malawi on zoonotic leishmaniasis. Officially, Leishmania wasn’t thought to exist in Zambia, but our research found clear cases in dogs. That led to further investigation, revealing high infection rates in certain areas. The goal is simply to share this reality with people in Zambia.
In Malawi, Leishmania is reported, but Zambia wasn’t even considered endemic by WHO. We looked into it and found otherwise. It doesn’t matter who conducts the investigation—as long as someone with the skills steps in, it’s valuable.

*AMED: Japan Agency for Medical Research and Development

Osawa:
So the key is not necessarily being Japanese, but knowing your strengths and being willing to explore uncharted areas. That seems crucial moving forward.

Goto:
Currently in Japan, I believe there are only about three groups focusing primarily on Leishmania research: our lab, Dr. Hamano* at Nagasaki University, and Dr. Kato* at Jichi Medical University. Dr. Hamano has a strong background in vaccine development for Leishmania, while Dr. Kato is known for his research on sandflies and epidemiological studies in South America. That said, it’s impossible for just three groups to cover all aspects of Leishmania research. It would be great if the research community on Leishmania grew, but we’re also facing a decline in parasitology departments at Japanese universities. With this overall shrinking trend, Japanese parasitology research is heavily skewed toward malaria. Of course, considering severity and patient numbers, malaria does take priority over other parasitic diseases. However, the distribution of researchers seems unbalanced—there are so many Leishmania researchers in the U.S., but not nearly as many in Japan. I do wish we had more momentum here. With fewer researchers in the Leishmania field compared to malaria, it creates a relatively less competitive environment for conducting research.

*Dr. Hamano: Dr. Shinjiro Hamano, Professor, Department of Parasitology, Institute of Tropical Medicine, Nagasaki University
*Dr. Kato: Dr. Daichi Kato, Professor, Department of Infectious Diseases and Immunology, Jichi Medical University

Osawa:
Did you formally propose your findings about Leishmania in Zambia to the Zambian government?

Goto:
Leishmaniasis is a zoonotic disease, so if infected dogs are found, there’s a high chance that humans are infected too. After obtaining permission from the Zambian government to conduct human studies, we did indeed confirm positive cases among people. But the reality is, most locals have never even heard of the disease. Many people suffer from unexplained symptoms—fever, anemia, and spleen enlargement—that aren’t caused by malaria or tuberculosis. In Japan, a diagnosis might be reached through exclusion, but in Zambia, the process often stops without an answer. In countries where Leishmaniasis is recognized as endemic, WHO provides medications. However, Zambia had no reported cases, so no treatments were available. Once the infection rate and presence of the disease are officially reported, the government can act, and treatments can be distributed even without national financial burden.

Osawa:
When you make such proposals to the government, who are your counterparts?

Goto:
We try to involve people who already understand the issue. If we involve high-ranking officials in the project from the beginning, it prevents the process from being shut down later on, compared to trying to escalate things from the bottom up. Our coordinators have done a great job facilitating this, and even the top officials in the relevant Zambian government agencies are now part of our team.

Osawa:
What are your goals or dreams moving forward?

Goto:
I have about 15 years left until retirement, but I don’t feel like I’ll finish all the research I’ve started. I always try to quietly pursue research that I—and others—believe is important and interesting.

There are a few things I’d like to accomplish. First, I want to develop new medications. While amphotericin B is currently used for visceral leishmaniasis, it has many side effects. I’d like to create better drugs, not just antiparasitics that directly target the parasite, but also ones that modulate the immune system—something like immunotherapy. If we only develop drugs that kill pathogens outright, resistance is inevitable. I believe balancing the immune response is a better way to treat disease.

Also, since Leishmania is very good at manipulating the host’s immune system, I’d like to identify the substances it uses to do this and repurpose them to develop treatments for autoimmune diseases.

Osawa:
That sounds like a fascinating idea—using knowledge of Leishmania’s interaction with the immune system to develop treatments for autoimmune conditions. Do you have any other plans?

Goto:
I’ve been working on a website called “Parasite Mimetics.” The idea is to create products that mimic the properties of parasites without using the actual organisms. For example, I’ve proposed using Leishmania’s ability to influence macrophages in cancer therapy. Dr. Shimokawa* at National Institute of Infectious Diseases has discussed how helminths might be used to treat type 1 diabetes. The site also includes a project to build a nationwide map of parasitology researchers in Japan. Our academic societies often lack a comprehensive view of who is working on what, so I thought having such a reference tool would be helpful.

*Parasitomimetics: Parasitomimetics
*Dr. Shimokawa: Dr. Chikako Shimokawa (Head, Division of Parasitology, National Institute of Infectious Diseases)
*Map of Parasite: Researchers: Map of Parasite Researchers

Osawa:
Do you have any advice or comments for student members of the Japanese Society of Tropical Medicine?

Goto:
There are many diseases that may not be common in our immediate surroundings but are affecting large populations globally. Recognizing these diseases and working toward countermeasures is extremely important in our increasingly globalized world. During COVID-19, for example, Japan significantly underestimated the threat of infectious diseases. Although Japan is classified as a moderately high-burden country for tuberculosis, the issue is rarely discussed.

It’s important to focus on cancer, cardiovascular disease, and diabetes, of course—but I think it’s also incredibly exciting and meaningful to engage in global research on tropical diseases that still need much more attention worldwide.

Making Science More Accessible

Goto:
There’s a big difference between learning about something through the internet and seeing it with your own eyes.

We run a program that gives high school students across Japan the opportunity to experience genetic engineering experiments firsthand. We lend out compact electrophoresis and PCR machines to schools free of charge. After moving to Tokyo, I was surprised at how many more opportunities are available here compared to rural areas. Even in the digital age, accessing quality scientific information remains a challenge for people in the countryside. Private schools in Tokyo often have access to proper lab equipment and reagents, but many public schools in rural areas don’t. That’s why we lend our equipment to them. Experiencing these experiments firsthand really helps students understand what’s written in their textbooks.

Osawa:
Yes, things we study at our desks are easy to forget, but experiments really stick in your mind.

Goto:
We also run a collaborative program with students from Joshibi University of Art and Design. They illustrate research from University of Tokyo students in an accessible and engaging way. Explaining research to people who don’t have a science background and helping them understand it is a learning experience in itself. By sharing this kind of content, we hope to get more people interested in life sciences—and ideally, even in parasitology.

If more people had scientific literacy, we’d see fewer people spreading or believing in misinformation. That ultimately comes down to education. I hope that through hands-on science and lab experiments, we can raise the overall level of scientific knowledge in Japan.

Profile of Interview Participants

Dr. Yasuyuki Goto
Professor, Department of Animal Resoucrce Sciences, Graduate School of Agricultural and Life Sciences / Faculty of Agriculture, The University of Tokyo. Originally from Nobeoka City, Miyazaki Prefecture. After graduating from the Department of Animal Life Systems Science, Faculty of Agriculture, The University of Tokyo, he earned his Ph.D. from the Graduate School of Agricultural and Life Sciences in the same field. He conducts broad-ranging research on leishmaniasis, from basic immunology to disease pathogenesis and therapeutic development. He also aims to utilize the immunomodulatory effects of parasites to develop new treatments for autoimmune diseases. He is actively involved in science education and outreach, including programs for high school students.

Ayaka Osawa
Fourth-year student, School of Dentistry, Kyushu Dental University.
Originally from Shiga Prefecture. Inspired by her entomologist father, she has been interested in insects, parasites, and bacteria since childhood. Currently, she is conducting research on periodontal pathogenic bacteria. In the future, she hopes to support people’s health as a clinician while also promoting the importance of oral health and contributing to the advancement of preventive medicine worldwide.