Event
CHBE Seminar: Dr. Rosangela Mezghanni, UMSOM
Friday, February 27, 2026
11:00 a.m.
Room 2108 Chemical and Nuclear Engineering Building
Patricia Lorenzana
301-405-1935
plorenza@umd.edu
“Epigenetic Control of Innate Immunity: Trained Immune Responses and Salmonella Typhi Infection”
Abstract: Trained immunity is an emerging concept that challenges the traditional belief that only adaptive immune cells possess memory. It refers to the capacity of the innate immune system to "remember" prior infections or vaccinations and mount enhanced responses upon re-exposure, even to unrelated pathogens. Unlike adaptive immunity, trained immunity is driven by epigenetic reprogramming of innate immune cells, resulting in heightened cytokine production. When combined with adaptive responses, this forms a potent and durable defense now referred to as “Integrated Organ Immunity”.
A central question remains: how does epigenetic memory persist in proliferating cells? In this seminar, I will first review our previous work demonstrating that both epithelial cells and Salmonella Typhi infection can induce chromatin changes in innate lymphocytes, using advanced in vitro models of intestinal mucosa.
Next, I will present unpublished data from a human typhoid vaccination–challenge study involving volunteers randomized into three arms: placebo, a suboptimal vaccine candidate, and the licensed Ty21a vaccine (with up to 92% efficacy). Participants were sampled longitudinally for epigenetic analyses to explore the durability of memory in dividing cells.
We will conclude with a discussion of the biological significance of these findings for vaccine development and the possible underlying mechanisms.
Bio: Dr. Rosangela Mezghanni is an associate professor of Pediatrics at the Center for Vaccine Development and Global Health (CVD), University of Maryland Baltimore (UMB). She came to CVD in 2000 after receiving her PhD in Microbiology & Immunology from Paris Descartes University. Her research focuses on adaptive and innate cell responses, including their activation, expansion, and epigenetic modifications in response to gastrointestinal pathogens and oral vaccines. She has extensive training in human Mucosal Immunology and tissue engineering, along with more than 20 years of experience designing, directing, and reporting clinical studies to evaluate vaccine immunogenicity and safety.
