Ivan Kairatov’s career has been defined by a relentless pursuit of innovation in regenerative medicine and drug development, particularly in the complex landscape of biopharmaceuticals. With a deep background in the mechanics of the human immune system and extensive experience in research and development, Kairatov has often looked for ways to bridge the gap between laboratory breakthroughs and scalable clinical applications. Today, he shares his expert insights on a transformative development in stem cell biology: the ability to generate a renewable and expandable supply of progenitor immune cells. Our conversation delves into the shift away from traditional hematopoietic stem cell reliance, the technical hurdles of mature macrophage therapy, the engineering of “off-the-shelf” immunotherapies, and the promising results seen in treating both aggressive tumors and inherited immune failures.
The traditional understanding of hematology has long held that only hematopoietic stem cells possess the capacity for long-term self-renewal. How does the discovery that granulocyte-monocyte progenitors can be maintained indefinitely change our approach to developing new therapies?
This discovery is essentially a seismic shift because it shatters what we previously considered a “glass ceiling” for progenitor cells. By utilizing a specific chemical cocktail, the researchers led by Qi-Long Ying at the Keck School of Medicine of USC have proven that these cells can divide extensively without losing their identity or their ability to become functional immune cells. In the past, we were limited by the scarcity and complexity of hematopoietic stem cells, which can generate any type of blood cell but are much harder to manage. Now, we have a scalable starting point that is already “committed” to becoming the specific macrophages and immune cells we need for therapy. It feels like we’ve found a way to keep a specialized factory running at peak efficiency indefinitely, ensuring we always have the raw materials needed to fight disease without having to start from scratch for every single treatment cycle.
Macrophages are naturally suited to infiltrate solid tumors, yet they are notoriously difficult to manufacture and store for clinical use. Could you describe the specific technical hurdles of working with mature macrophages and why focusing on their “upstream” ancestors is a more viable strategy?
The primary struggle is that mature macrophages are quite delicate and do not take well to being manipulated or expanded outside the human body, which has historically limited our ability to create large-scale doses. They are difficult to expand to the high numbers required for effective therapy, and they often sustain significant damage during the freezing and storage processes that are essential for global distribution. Furthermore, when these mature cells are injected into a patient, they have a frustrating tendency to accumulate in the liver or the lungs rather than navigating through the blood to reach the actual tumor site. By shifting our focus “upstream” to the granulocyte-monocyte progenitors, or GMPs, we bypass these fragile end-stage cells entirely. We are instead working with a more robust, engineerable foundation that can be grown long-term in a laboratory and then differentiate into functional cells exactly where they are needed most.
The study highlights the use of chimeric antigen receptors and additional signaling molecules to enhance these progenitor cells. How does this engineering facilitate an “off-the-shelf” treatment model, and why is that such a critical milestone for patients who may not have time for personalized manufacturing?
The “off-the-shelf” model is the holy grail of immunotherapy because it removes the agonizing weeks-long waiting period required to manufacture a bespoke treatment from a patient’s own cells. By engineering these GMPs to recognize specific cancer markers while also carrying an additional signal to activate nearby tumor-fighting T cells, we create a potent dual-action weapon that works even when the donor and recipient are immunologically mismatched. This means that a single donor’s cells could potentially be manufactured in advance and given to many different patients the moment they are diagnosed. For a patient with a rapidly progressing solid tumor, having a potent, pre-manufactured treatment ready to go on day one is not just a convenience—it is a life-saving necessity that changes the entire emotional and clinical landscape of their care.
One of the most striking results of the mouse trials was the ability of the engineered progenitors to engraft into the bone marrow. What are the clinical implications of having a therapy that constantly replenishes itself from within the body’s own blood-forming niches?
This engraftment is a total game-changer because it directly solves the problem of “rapid clearance,” where therapeutic cells are flushed out of the patient’s system before they can finish the job. When the GMPs take up residence in the bone marrow and other blood-forming niches, they essentially turn the patient’s own body into a localized production hub for engineered macrophages. We saw this in the data where the cells kept replenishing the supply of tumor-fighting units, providing a level of persistence that simply isn’t possible with a one-time injection of mature cells that are quickly cleared. It is the difference between sending a single wave of soldiers into a fight versus establishing a permanent outpost that can continuously deploy fresh reinforcements until the threat is neutralized. This persistent presence allows the therapy to delay disease progression far more effectively over the long term.
While much of the focus is on oncology, the research also successfully restored immune function in mice with chronic granulomatous disease. What does this suggest about the versatility of the GMP platform for treating non-cancerous conditions or inherited immune deficiencies?
It suggests that we aren’t just building a tool for oncology; we are building a versatile platform for repairing or upgrading the human immune system at its core. By restoring the ability of mice to fight off bacterial infections, the researchers proved that these engineered progenitors can successfully fill a functional void caused by a genetic defect. For patients with inherited deficiencies, where their body literally lacks the genetic “code” to create functional, germ-fighting immune cells, this technology offers a way to insert a functional and renewable population of cells. It is a profoundly hopeful prospect to think that a single intervention could potentially “patch” an immune system for life, protecting a person from the constant, terrifying threat of simple infections that their body otherwise couldn’t handle.
What is your forecast for the future of progenitor cell-based immunotherapies over the next decade?
In the next ten years, I expect a fundamental shift where self-renewing progenitor cells, rather than mature immune cells, become the gold standard for all complex cellular therapies. We will likely see the first successful human clinical trials for CAR-GMPs targeting solid tumors that were previously considered “cold” or unreachable by standard T-cell therapies. The scalability of the chemical cocktail method will enable large-scale manufacturing hubs to produce standardized immune “seeds” that can be shipped globally, significantly reducing the cost and complexity of care. Ultimately, we are moving toward a future where “programmable” immunity becomes a standard part of medicine, allowing us to treat everything from rare genetic disorders to aggressive cancers with a level of precision and longevity that was once thought impossible.
