Scientists at Cincinnati Children's have identified how certain immune cells are molecularly programmed to respond faster when the body encounters a familiar threat, shedding light on immune memory and its links to diseases such as asthma, multiple sclerosis and inflammatory bowel disease.
The study, published March 26, 2026 , in Cell Reports, found that "memory" CD4⁺ T cells — immune cells formed after infection or vaccination — have their DNA primed to activate key defense genes within hours. In contrast, naïve T cells encountering a pathogen for the first time can take days to mount a response.
The difference lies in the cells' epigenome — chemical and structural features that control how easily genes can be turned on.
"Although the rapid recall phenomenon is well known, the underlying mechanisms are poorly understood," says Emily Miraldi, PhD , a computational biologist at Cincinnati Children's and senior author of the study. "Here, we use single-cell genomics and gene regulatory network modeling to pinpoint the transcription factors that bind DNA to keep memory cells prepared for fast, potent immune defense."
DNA already set for action
Using advanced single‑cell analysis techniques, the researchers studied tens of thousands of human CD4⁺ T cells from four donors, tracking gene activity and chromatin accessibility — a measure of how exposed regulatory DNA regions are — before and after activation.
They found that many regulatory regions controlling immune response genes are already accessible in resting memory T cells, giving them a head start when a known pathogen reappears.
"Memory cells don't start from the same baseline," said co-first author Alexander Katko, a PhD candidate in immunobiology. "Many of the regulatory regions that control rapid immune responses are already open in resting memory cells."
Key regulators identified
The study identified five transcription factors — proteins that control gene activity — that consistently distinguish memory T cells from naïve cells. These include KLF6, MAF, PRDM1, RUNX2 and SMAD3.
Together, these regulators form a core network that maintains immune readiness during long periods of rest and drives rapid activation during recall responses.
"This work moves us beyond individual genes," says Artem Barski, PhD , a member of the divisions of Allergy and Immunology and of Human Genetics at Cincinnati Children's and co‑senior author on the study. "It shows how networks of regulators work together to control immune memory."
Links to disease risk
The team built a mathematical model of these regulatory networks and validated it using data from more than 100 additional individuals, as well as samples from people undergoing peanut oral immunotherapy.
They then integrated the model with large genetic studies and found that many DNA variants associated with asthma, allergic disease and autoimmune diseases fall within memory‑specific regulatory regions.
These variants do not alter proteins themselves. Instead, they appear to affect how quickly or strongly immune response genes are activated — potentially contributing to overactive or poorly controlled immune responses.
Potential implications
The findings may help guide future efforts to design vaccines that produce faster or stronger immune protection, such as for elderly people who often do not respond robustly to standard vaccines. Meanwhile, the findings could help scientists develop treatments that more precisely target harmful immune responses without broadly suppressing immunity.
"This gives us a systems‑level map of how immune memory is maintained," Barski said. "That foundation can help us better understand — and eventually better control — immune responses in health and disease."
About the study
The Cincinnati Children's research team also included co-first author Svetlana Korinfskaya, PhD, in the Division of Allergy and Immunology as well as Anthony Bejjani, Seyifunmi Owoeye, Zi F. Yang, Akshata Rudrapatna, Sarah Potter, PhD, Joseph Wayman, PhD, Michael Kotliar, and Leah Kottyan, PhD. The Cincinnati Children's Single Cell Genomics Facility also contributed to the study.
Funding sources included several grants from the National Institute of Health (R01AI153442, U01AI150748, R01AI173314, R42HG011219, and P30AR070549)
