Episode 548: When Infections Leave a Mark: How the Immune System Remembers and Shapes Alzheimer’s | Dr. Betsy Bradshaw

Overview This special episode of the [Tick Boot Camp Podcast](https://tickbootcamp.com/podcast/) was recorded live at the 2nd Annual Alzheimer’s Pathobiome Initiative (AlzPI) and PCOM Symposium in collaboration with Pathobiome Perspectives. Hosted by Ali Moresco in partnership with Nikki Schultek, Executive Director of AlzPI, the conversation continues the Tick Boot Camp mission of exploring infection-associated chronic illness (IACI)—including Lyme disease and other tick-borne infections—within the global Alzheimer’s and neuroimmunology research community. Tick Boot Camp co-founders Matt Sabatello and Rich Johannesen partnered with Ali and Nikki to highlight leading scientists connecting microbes, immune dysregulation, and neurodegenerative disease. This episode features Dr. Elizabeth “Betsy” Bradshaw, Assistant Professor of Neurology at Columbia University Irving Medical Center, whose research investigates how past infections leave lasting imprints on the brain’s immune system and influence the development of Alzheimer’s disease. Guest Elizabeth M. Bradshaw, PhD Assistant Professor of Neurology, Columbia University Irving Medical Center Principal Investigator, Bradshaw Laboratory – Neuroimmunology and Genetics of Alzheimer’s Dr. Bradshaw’s laboratory focuses on the immune system’s role in neurodegeneration, particularly how infection and inflammation alter brain immunity and predispose individuals to conditions like Alzheimer’s disease. Her work builds on large-scale genome-wide association studies (GWAS) that identified immune-related genetic variants linked to Alzheimer’s susceptibility, suggesting that subtle changes in immune function—not just neuronal factors—may underlie disease onset. Her team is exploring how pathogens such as HSV-1 (Herpes Simplex Virus Type 1) interact with the brain’s immune cells, known as microglia, and how these infections can “reprogram” immune responses long after the pathogen is cleared. Key Discussion Points Dr. Bradshaw explains how her research bridges genetics, immunology, and infectious disease to better understand Alzheimer’s. Through GWAS data, her team found that many of the genes linked to Alzheimer’s risk involve immune pathways rather than neuronal signaling. This discovery redirected the field’s attention toward how immune cells respond to pathogens and environmental stressors across a lifetime. Using human-derived microglia-like cells created from blood monocytes, her team observes how infections reshape immune cell metabolism and memory. By infecting these microglia-like cells with Alzheimer’s-associated pathogens like HSV-1, they study how genetic background and infection history determine immune cell behavior. The findings suggest that past infections may epigenetically and metabolically train microglia—changing how they respond to aging, stress, and amyloid buildup. Even when the infection has resolved, these “reprogrammed” immune cells can remain altered for decades, silently increasing the brain’s vulnerability to neurodegeneration. Dr. Bradshaw emphasizes that understanding how infections rewire the brain’s immune landscape could transform early intervention strategies. Identifying combinations of genetic risk factors and pathogen exposures may enable targeted prevention or immune-modulating treatments long before symptoms appear. “Microglia remember. Even after the pathogen is gone, they carry its imprint—responding differently decades later when the brain faces new challenges.” — Dr. Elizabeth Bradshaw Why It Matters Dr. Bradshaw’s work reframes Alzheimer’s disease as a neuroimmune condition shaped by infection and host genetics. Her research highlights how microbial exposures, immune history, and inflammation converge to influence cognitive decline. By integrating infection biology with genetics and immunology, her team is redefining how scientists and clinicians view the root causes of Alzheimer’s and other neurodegenerative diseases. This work strengthens the growing case that the immune system’s “memory” of infection may be one of the most important and overlooked factors in brain health and aging. About the Event This interview was recorded at the 2nd Annual Alzheimer’s Pathobiome Initiative (AlzPI) and Philadelphia College of Osteopathic Medicine (PCOM) Symposium, held October 3, 2025, at Ohio University in Dublin, Ohio. The event brought together more than 20 leading researchers exploring how microbes, the microbiome, and immune dysregulation contribute to Alzheimer’s, dementia, and infection-associated chronic illness (IACI). Tick Boot Camp partnered with Ali Moresco and Nikki Schultek to share these conversations and connect chronic Lyme, infection, and neurodegenerative research communities. Learn More Learn more about the Alzheimer’s Pathobiome Initiative (AlzPI) Listen to Tick Boot Camp Podcast episodes, including Episode 406: Pathobiome – An ...