Core Framework & Diagram What Is Immune Reprogramming?
July 23, 20261 Min Read The Future of CAR-T
July 23, 2026If we could rewrite immune cells' 'working rules,' disease treatment would enter an entirely new dimension
—— Immune Reprogramming: rewriting the correct instructions into an incorrectly running immune program.
I. Epigenetic reprogramming: change cells' 'way of working' without changing DNA
DNA is the cell's 'genetic script' — it determines what proteins cells can synthesize. But which lines of the script get read, and which are skipped, is determined by 'epigenetics': DNA methylation, histone modifications (acetylation, methylation, etc.) — like annotations and marks on the script, they determine which genes are expressed. Epigenetic markers are less stable than DNA sequences — they can be changed by environment, life experiences, drugs, microbes, and even food components. And changed epigenetic states can be passed to daughter cells when cells divide — this is 'epigenetic memory.' In immune reprogramming, epigenetic modification is one of the most persistent and deepest changes.
Trained immunity — after BCG or β-glucan activates monocytes, H3K4me3 (an activating histone modification) permanently increases in the promoter regions of inflammatory genes, letting these genes be activated faster and more strongly under future stimulation. This epigenetic change can be maintained in monocytes for months to years — this is precisely the molecular basis of 'innate immune memory.' TET2 knockout in CAR-T — TET2 is a DNA demethylase playing an important role in CD8+ T cells' exhaustion program. CRISPR knockout of TET2 changed CAR-T cells' DNA methylation pattern, biasing them toward a 'stem-like memory T cell' direction, significantly enhancing CAR-T's persistence and anti-tumor effects (from a case report at the University of Pennsylvania: one CLL patient achieved complete remission after CRISPR-TET2 CAR-T treatment, published in Nature 2018).
2. CAR technology: installing 'new operating system applications' on immune cells
CAR (Chimeric Antigen Receptor) technology is one of the most widely applied immune reprogramming tools currently. In the immune reprogramming framework, CAR technology's essence is 'receptor-level rule rewriting': the original rules: T cells only recognize specific peptide fragments presented by MHC (requiring APC training, requiring MHC matching); the new rules: CAR-T cells directly recognize specific proteins on any cell surface (without MHC, without prior training). This rule rewriting upgrades T cells' recognition capability from 'can only read MHC-presented business cards' to 'can directly identify any marker on a target' — a reprogramming that fundamentally expanded T cell functional boundaries.
Further reprogramming through CRISPR stacking on CAR-T cells: knocking out PD-1 (removing the brake after activation); knocking out TET2 (enhancing persistence); introducing IL-15 secretion circuits (letting CAR-T self-sustain in the body); deleting HLA genes (creating universal products) — each step adds new 'patches' or 'upgrade modules' to the existing rules.
3. Metabolic reprogramming: changing immune cells' energy strategy to change functional orientation
Metabolic reprogramming artificially intervenes in these metabolic programs, thereby changing immune cells' functional orientation: AMPK activation (like metformin or exercise-activated pathways) — AMPK is the cell's energy sensor; activation inhibits mTORC1, pushing immune cells from aerobic glycolysis toward oxidative phosphorylation, associated with reducing pro-inflammatory states and enhancing immune memory formation; HIF-1α inhibition — HIF-1α is the hypoxia-inducible factor that activates glycolysis genes and promotes pro-inflammatory factor production. Targeting HIF-1α in the tumor microenvironment can partially reverse tumor cells' and immune cells' metabolic switches, improving immune cell function inside tumors.
Ketone body BHB's inflammasome inhibition — ketone body β-hydroxybutyrate (BHB) produced by fasting and ketogenic diets directly inhibits the NLRP3 inflammasome, reducing IL-1β and IL-18 secretion — a direct example of changing immune cells' functional programs through metabolic substrates. In vitro CAR-T metabolic optimization — during the ex vivo manufacturing process of CAR-T cells, through selection of culture medium composition and cytokines, optimizing CAR-T cells' metabolic state (biasing toward 'memory-type' metabolism of oxidative phosphorylation), making them have better persistence and anti-exhaustion capacity after reinfusion.
4. Hematopoietic stem cell transplantation: the most thorough systemic immune reset
Among all immune reprogramming means, hematopoietic stem cell transplantation (HSCT) is the most thorough — not changing existing immune cells' programs, but using new hematopoietic stem cells to rebuild the entire immune system. HSCT logic: first use high-intensity chemotherapy or radiation (conditioning regimen) to clear existing abnormal immune cells (and bone marrow blood stem cells); then infuse donor (allogeneic) or self (autologous) hematopoietic stem cells to rebuild a new immune system.
In autoimmune disease (Article 65 covered this in detail), autologous HSCT results are remarkably positive: after transplantation, previously self-tissue-attacking autoreactive T cells are cleared; newly growing T cells, under re-thymic selection, establish new tolerance to self-tissue. In refractory multiple sclerosis patients, HSCT's long-term disease-free remission rate, in some studies, exceeded any other treatment option. HSCT's costs are real: conditioning regimen toxicity, infection risk, transplant-related mortality (usually below one to five percent at specialized centers, but still not negligible). This is a risk-benefit weighing decision, not an ordinary 'reset button.' But it represents the most thorough principle in immune reprogramming: when a system's program errors are too fundamental to correct through patching, reinstalling the operating system may be the only effective option.
|
HSCT is one of medicine's means to truly 'restart' — using completely new hematopoietic stem cells to rebuild an immune system with no historical errors. In the right patients, right indication, right center, this 'restart' can change disease trajectories. |
5. Immune reprogramming's ethical frontier: how far can we go?
As CRISPR, CAR technology, and hematopoietic stem cell transplantation advance, immune reprogramming's capabilities are rapidly expanding — not just treating diseases, but beginning to touch deeper questions: Can we 'program' the immune system to work like it does in youth, even in old age? Technically, thymus regeneration, NK cell supplementation, and epigenetic reprogramming's combination is beginning to approach some aspects of this goal. Can we 'program' the immune system to establish permanent tolerance to specific self-antigens (not just temporary suppression), truly curing autoimmune disease rather than lifelong dependence on immunosuppressants? Antigen-specific tolerance induction is attempting to answer this. Can we 'program' the immune system to not only respond to known threats but better identify new threats (novel viruses, new mutations in cancer cells)?
Every step forward comes with questions that must be seriously addressed: who can access these technologies (cost, accessibility)? What are these technologies' long-term effects and risks (especially CRISPR's off-target effects and unknown long-term consequences)? And in what contexts is using these technologies reasonable gain, and in what contexts inappropriate intervention in natural processes? These questions have no technical answers, only collective human value judgments. And this judgment needs to include patients, doctors, scientists, ethicists, policy makers, and enough ordinary public participation. This is precisely what this popular science series ultimately hopes to achieve — letting more people understand this revolution, then having the ability to participate in conversations about it.
Frequently Asked Questions