Preclinical Study Confirms Efficacy of Novel Cell Therapy Using iPS Cell-Derived NKT Cells — Potential to Strongly Elicit Patient-Specific Cancer-Reactive T Cells in Combination with Antigen-Presenting Cells —
A research group including Assistant Professor Takahiro Aoki, Professor Shinichiro Motohashi of Chiba University Graduate School of Medicine, and Team Director Akihiko Koseki of RIKEN Center for Integrative Medical Sciences, has clarified that strong anti-tumor effects can be obtained by combining iPS cell-derived "NKT cells" with "antigen-presenting cells presenting α-galactosylceramide." This combination therapy also increased cancer-reactive memory T cells in a mouse model transplanted with patient-derived lung cancer tissue and human immune cells, opening new avenues for personalized cell therapy.
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- 📰 Published: May 1, 2026 at 19:00
- 🔍 Collected: May 1, 2026 at 10:31
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The research group led by Assistant Professor Takahiro Aoki and Professor Shinichiro Motohashi of Chiba University Graduate School of Medicine, and Team Director Akihiko Koseki of RIKEN Center for Integrative Medical Sciences, has clarified that strong anti-tumor effects can be obtained by combining iPS cell-derived "NKT cells (Note 1)" with "antigen-presenting cells (Note 3) presenting α-galactosylceramide (Note 2)." Furthermore, this study confirmed that applying this combination therapy to a mouse model transplanted with patient-derived lung cancer tissue and human immune cells increased memory T cells that react to cancer. This achievement leads to a new cell therapy that elicits immune responses tailored to each patient's cancer.
The results of this research were published in Stem Cell Research & Therapy on April 23, 2026.
(Paper available here: 10.1186/s13287-026-04994-7)
Conceptual diagram of treatment effect
■ Background of Research
In immunotherapy for cancer, it is important to enhance the body's immune cells' ability to find and attack cancer cells. Among these, "NKT cells" have attracted attention as promising cells for cancer treatment due to their role as an immune command center, capable of activating other immune cells. However, stably securing NKT cells from cancer patients has been a challenge. Therefore, the research group has previously developed a technology to produce NKT cells from iPS cells based on healthy human cells. These iPS cell-derived NKT cells (Note 4) were thought to have the potential to promote a stronger immune response against cancer by activating them with α-galactosylceramide, but this effect had not yet been demonstrated.
■ Key Points of Research Results
① Our research group administered a combination of iPS cell-derived NKT cells and antigen-presenting cells presenting α-galactosylceramide, which activates NKT cells. It was found that tumor growth was more strongly suppressed when the two types of cells were used in combination than when either was used alone.
② A detailed examination of immune cells within the tumor revealed that only with this combination therapy were memory T cells strongly amplified.
③ Investigation of the T cell receptors of the increased T cells showed that they were indeed T cells that reacted to tumor cells. This treatment, therefore, showed the potential to promote the increase of T cells that identify and react to cancer.
④ In fact, when CCR7-positive cells, a marker for memory T cells, were removed, the anti-tumor effect was weakened, confirming the importance of these T cells in the treatment effect.
⑤ While it is difficult to collect sufficient NKT cells from cancer patients themselves, this study used "allogeneic" cells produced from iPS cells of healthy donors. This opened the way for an "off-the-shelf" treatment that can be used by anyone.
■ Future Prospects (Researcher Comments)
We believe that the results of this preclinical study demonstrate the possibility of personalized medicine using iPS cell-derived NKT cells to elicit T cell immunity tailored to each patient's cancer. Clinical trials are currently being conducted for advanced head and neck cancer using this combination therapy of iPS cell-derived NKT cells and patient-derived antigen-presenting cells, and we plan to confirm the efficacy of this treatment. While transplantation of ordinary T cells to another person often causes GVHD (graft-versus-host disease), NKT cells are characterized by their potential for relatively safe use in treatment, as they are not limited to specific leukocyte types and are less likely to cause GVHD, making them easily applicable to a wide range of patients. Moving forward, we aim to further verify long-term effects and efficacy in various cancer types to translate this into actual treatment.
■ Glossary
Note 1) NKT cells: Special lymphocytes that rapidly mobilize the body's immune system. They not only attack cancer cells themselves but also act on other immune cells to activate the overall immune system.
Note 2) α-galactosylceramide (αGalCer): A substance that strongly activates NKT cells. By incorporating it into antigen-presenting cells, it can activate NKT cells.
Note 3) Antigen-presenting cells: Cells that take in information (antigens) from foreign substances or cancer cells that have invaded the body and present their characteristics to immune cells. This triggers an immune response as T cells and NKT cells recognize the target.
Note 4) iPS cell-derived NKT cells: NKT cells artificially produced from iPS cells. They have the potential to be stably supplied even when it is difficult to collect sufficient NKT cells from the patient themselves.
■ Paper Information
Title: Preclinical efficacy of combination therapy with allogeneic induced pluripotent stem cell-
Keywords:
The results of this research were published in Stem Cell Research & Therapy on April 23, 2026.
(Paper available here: 10.1186/s13287-026-04994-7)
Conceptual diagram of treatment effect
■ Background of Research
In immunotherapy for cancer, it is important to enhance the body's immune cells' ability to find and attack cancer cells. Among these, "NKT cells" have attracted attention as promising cells for cancer treatment due to their role as an immune command center, capable of activating other immune cells. However, stably securing NKT cells from cancer patients has been a challenge. Therefore, the research group has previously developed a technology to produce NKT cells from iPS cells based on healthy human cells. These iPS cell-derived NKT cells (Note 4) were thought to have the potential to promote a stronger immune response against cancer by activating them with α-galactosylceramide, but this effect had not yet been demonstrated.
■ Key Points of Research Results
① Our research group administered a combination of iPS cell-derived NKT cells and antigen-presenting cells presenting α-galactosylceramide, which activates NKT cells. It was found that tumor growth was more strongly suppressed when the two types of cells were used in combination than when either was used alone.
② A detailed examination of immune cells within the tumor revealed that only with this combination therapy were memory T cells strongly amplified.
③ Investigation of the T cell receptors of the increased T cells showed that they were indeed T cells that reacted to tumor cells. This treatment, therefore, showed the potential to promote the increase of T cells that identify and react to cancer.
④ In fact, when CCR7-positive cells, a marker for memory T cells, were removed, the anti-tumor effect was weakened, confirming the importance of these T cells in the treatment effect.
⑤ While it is difficult to collect sufficient NKT cells from cancer patients themselves, this study used "allogeneic" cells produced from iPS cells of healthy donors. This opened the way for an "off-the-shelf" treatment that can be used by anyone.
■ Future Prospects (Researcher Comments)
We believe that the results of this preclinical study demonstrate the possibility of personalized medicine using iPS cell-derived NKT cells to elicit T cell immunity tailored to each patient's cancer. Clinical trials are currently being conducted for advanced head and neck cancer using this combination therapy of iPS cell-derived NKT cells and patient-derived antigen-presenting cells, and we plan to confirm the efficacy of this treatment. While transplantation of ordinary T cells to another person often causes GVHD (graft-versus-host disease), NKT cells are characterized by their potential for relatively safe use in treatment, as they are not limited to specific leukocyte types and are less likely to cause GVHD, making them easily applicable to a wide range of patients. Moving forward, we aim to further verify long-term effects and efficacy in various cancer types to translate this into actual treatment.
■ Glossary
Note 1) NKT cells: Special lymphocytes that rapidly mobilize the body's immune system. They not only attack cancer cells themselves but also act on other immune cells to activate the overall immune system.
Note 2) α-galactosylceramide (αGalCer): A substance that strongly activates NKT cells. By incorporating it into antigen-presenting cells, it can activate NKT cells.
Note 3) Antigen-presenting cells: Cells that take in information (antigens) from foreign substances or cancer cells that have invaded the body and present their characteristics to immune cells. This triggers an immune response as T cells and NKT cells recognize the target.
Note 4) iPS cell-derived NKT cells: NKT cells artificially produced from iPS cells. They have the potential to be stably supplied even when it is difficult to collect sufficient NKT cells from the patient themselves.
■ Paper Information
Title: Preclinical efficacy of combination therapy with allogeneic induced pluripotent stem cell-
Keywords: