By admin 
Neuroblastoma represents the most significant clinical challenge in pediatric oncology as the most common extracranial solid tumor diagnosed in children, primarily arising within the developing sympathetic nervous system. While medical advancements have improved outcomes for many childhood cancers, approximately 50% of neuroblastoma patients are diagnosed with high-risk disease, a classification characterized by aggressive tumor growth, genetic mutations such as MYCN amplification, and a daunting 50% long-term survival rate. The clinical landscape becomes even more dire for children whose high-risk neuroblastoma relapses after intensive frontline chemotherapy, as the overall survival rate for these patients plummets to below 20%. For the small percentage of children who do survive this grueling regimen, the victory often comes at a steep price; survivors frequently endure lifelong treatment-related toxicities, including hearing loss, cardiac issues, and an increased susceptibility to secondary malignancies.
In response to this urgent medical need, Dr. Hunter Jonus, PhD, a distinguished CureSearch Young Investigator based at Emory University’s Department of Pediatrics, is spearheading a transformative approach to treatment through cellular immunotherapy. Dr. Jonus’s research focuses on the utilization of gamma delta ($gammadelta$) T cells, a unique subset of immune cells that possess the potential to revolutionize how solid tumors are treated in pediatric patients. By engineering these cells to better recognize and destroy cancer, Dr. Jonus is moving the field toward a future where treatments are not only more effective but also significantly less toxic than traditional chemotherapy and radiation.
The Biological Challenge of High-Risk Neuroblastoma
Neuroblastoma typically originates in the adrenal glands but can also develop in nerve tissues along the abdomen, chest, or spine. It is a disease of the "embryonal" nervous system, meaning it begins in cells that were intended to become mature nerve cells. In high-risk cases, these cells fail to mature and instead proliferate uncontrollably, often spreading to the bone marrow, liver, and lymph nodes before a diagnosis is even made.
The current standard of care for high-risk neuroblastoma is among the most intensive in all of medicine. It generally involves a multi-modal approach: induction chemotherapy to shrink the tumor, surgical resection, high-dose chemotherapy followed by autologous stem cell transplantation, radiation therapy, and finally, immunotherapy using monoclonal antibodies. Despite this "kitchen sink" approach, the high rate of recurrence suggests that microscopic "seed" cells often survive the onslaught, leading to relapse.
Furthermore, the biological "cold" nature of neuroblastoma tumors—meaning they do not naturally trigger a strong immune response—makes them difficult to treat with conventional immunotherapies that have worked in adult cancers, such as checkpoint inhibitors. This is where the work of Dr. Jonus and her team at Emory University becomes critical, as they seek to "prime" the immune system to recognize these elusive cancer cells.
Pioneering Gamma Delta ($gammadelta$) T Cell Therapy
The cornerstone of Dr. Jonus’s research is the gamma delta T cell. Unlike the more common alpha-beta ($alphabeta$) T cells used in many current CAR-T therapies, $gammadelta$ T cells are unique because they bridge the gap between the innate and adaptive immune systems. One of their most significant advantages is their ability to recognize and kill tumor cells without the need for Major Histocompatibility Complex (MHC) presentation. Many tumors, including neuroblastoma, "hide" from the immune system by downregulating MHC molecules; $gammadelta$ T cells are not fooled by this tactic.
Dr. Jonus’s methodology involves extracting these $gammadelta$ T cells from healthy donors, rather than the patients themselves. This is a crucial distinction, as children undergoing intensive chemotherapy often have compromised or "exhausted" immune systems. By using healthy donor cells, the research team ensures a robust starting population of "soldiers." These cells are then expanded ex vivo (outside the body) using specialized laboratory techniques to create a massive army of therapeutic cells ready for infusion.
This research has transitioned from the laboratory to the clinic through a first-in-child clinical trial currently underway at Children’s Healthcare of Atlanta. In this trial, $gammadelta$ T cells are being combined with standard chemoimmunotherapy. The goal is to determine if the infusion of these healthy, expanded immune cells can provide a synergistic effect, clearing the remaining cancer cells that chemotherapy alone might miss.
Engineering the Future: CARs and Cytokine Integration
While the initial clinical trials are a major milestone, Dr. Jonus is already looking toward the next generation of cellular engineering to improve efficacy. A primary focus of her future work involves the development of Chimeric Antigen Receptors (CARs) specifically designed for $gammadelta$ T cells. By engineering these cells to express CARs, researchers can give them a "GPS system" that specifically targets proteins found on the surface of neuroblastoma cells, such as GD2 or B7-H3.
However, targeting the tumor is only half the battle. Solid tumors create a hostile microenvironment that can suppress or kill incoming immune cells. To combat this, Dr. Jonus is investigating ways to engineer $gammadelta$ T cells that can secrete their own cytokines. These cytokines act as a "life support system" for the T cells, helping them survive longer within the tumor and maintain their killing functionality.
"I am ecstatic to be selected as a CureSearch Young Investigator and for the opportunity to conduct this meaningful research with significant potential to impact patients’ lives," Dr. Jonus stated. "I am hopeful for the future of $gammadelta$ T cell immunotherapy and its possibility to overcome barriers in the field of adoptive cell therapy so that more patients will be able to receive this powerful treatment approach."
A Timeline of Progress in Neuroblastoma Research
The path to Dr. Jonus’s current clinical trial has been built on decades of incremental progress in pediatric oncology:
- 1990s: Identification of MYCN amplification as a primary biomarker for high-risk neuroblastoma, allowing for better risk stratification.
- 2000s: The introduction of high-dose chemotherapy with stem cell rescue becomes the standard of care for high-risk patients.
- 2010: The landmark clinical trial for Dinutuximab (an anti-GD2 antibody) shows significant improvement in event-free survival, leading to its FDA approval in 2015.
- 2018–2022: Early-stage research into $gammadelta$ T cells begins to show promise in laboratory models of solid tumors.
- 2023–2024: Dr. Jonus and her team launch the first-in-child clinical trial at Children’s Healthcare of Atlanta, integrating $gammadelta$ T cells into the frontline treatment protocol.
Addressing the Immune Checkpoint Barrier
A further layer of Dr. Jonus’s research involves the integration of immune checkpoint blockade. Cancer cells often express proteins that act as "brakes" on the immune system, effectively telling T cells not to attack. By combining $gammadelta$ T cell infusions with checkpoint inhibitors—drugs that release these brakes—Dr. Jonus aims to maximize the functionality and longevity of the therapeutic cells.
This multi-pronged approach—combining healthy donor cells, CAR engineering, cytokine secretion, and checkpoint blockade—represents one of the most comprehensive strategies currently being tested against pediatric solid tumors. It acknowledges that no single "silver bullet" is likely to cure high-risk neuroblastoma, but a sophisticated, engineered immune response might.
Broader Implications and Official Support
The implications of this research extend far beyond neuroblastoma. If $gammadelta$ T cell therapy proves successful and safe in children with neuroblastoma, it could provide a blueprint for treating other recalcitrant pediatric solid tumors, such as osteosarcoma and Ewing sarcoma, which have also seen stagnating survival rates over the last thirty years.
The support of CureSearch for Children’s Cancer is a testament to the potential of this work. CureSearch’s Young Investigator program is designed to provide funding to early-career scientists who are pursuing high-risk, high-reward research that has a clear path to clinical application. By funding Dr. Jonus, the organization is investing in a shift toward "precision medicine" in pediatrics—treatments tailored to the biological reality of the child’s specific cancer.
Medical analysts suggest that the success of these trials could lead to a significant reduction in the use of toxic, non-specific chemotherapies. "The goal is to move away from the ‘scorched earth’ policy of current treatments," says one oncology specialist. "If we can use a patient’s—or a donor’s—own immune system to do the work, we reduce the collateral damage to the child’s developing body."
Conclusion: A New Paradigm in Pediatric Oncology
The work of Dr. Hunter Jonus at Emory University and Children’s Healthcare of Atlanta represents a pivotal moment in the fight against high-risk neuroblastoma. By moving away from the limitations of autologous $alphabeta$ T cells and embracing the unique properties of donor-derived $gammadelta$ T cells, her team is addressing the core reasons why previous immunotherapies have struggled with solid tumors.
As the first-in-child clinical trial progresses, the pediatric oncology community remains cautiously optimistic. The transition from survival at any cost to survival with a high quality of life is the ultimate goal of the next generation of cancer research. Through the innovative application of cellular engineering and a deep understanding of the tumor microenvironment, Dr. Jonus is not just searching for a treatment; she is helping to define a new era of safer, more effective care for the most vulnerable patients.
