Date: Thursday 7th of May at 12:00 in Askja, N-132
Title: “Decoding immune cell consciousness: from epigenetic to cellular crosstalk and autoimmunity”
Speaker: Hossam A. Abdelsamed
Abstract: A cardinal feature of adaptive immunity is the ability to maintain long-lived immunological memory through antigen-independent homeostasis. Here, we show that maintenance of memory CD8 T cells’ effector potential during homeostatic proliferation is coupled to preservation of acquired DNA methylation programs, which remain stable over several rounds of cell division. These findings highlight the role of heritable epigenetic mechanisms in stabilizing T cell functional states. Building on this, we further investigated how such states may be reshaped through T-T cell crosstalk. We find that activated memory CD4 T cells drive naïve CD8 T cells toward activated/memory-like phenotypes in vitro and in vivo, which is functional and phenotypically autoreactive. Gene regulatory network analysis identifies enolase-1 (ENO1) as a key regulator of this process. Together, these results support a model in which stable epigenetic programs maintain T cell identity, while intercellular T-T cell crosstalk can reshape functional states.
Bio: Dr. Abdelsamed earned his PhD in Immunology and Microbiology from the University of Tennessee Health Sciences Center, where he identified a Th17-driven T cell response in hypersensitivity pneumonitis using mouse models and defined key roles for innate receptors in disease initiation. He completed a postdoctoral fellowship at St. Jude Children’s Research Hospital in the lab of Benjamin A. Youngblood, focusing on human T cell biology. His work on epigenetic regulation, particularly DNA methylation, led to the development of an epigenetic atlas of human CD8 T cell differentiation and contributed to studies of type 1 diabetes-specific T cells. This research resulted in multiple high-impact publications, including in NEJM, Cell, Nature, and Nature Immunology. He later joined the University of Pittsburgh School of Medicine as a research assistant professor, where he investigated immune tolerance and T cell cross-talk. In 2022, he published a senior-author study demonstrating that activated memory T cells can reshape the phenotype and transcriptome of autologous naïve T cells. In 2024, Dr. Abdelsamed joined the Augusta University (Medical College of Georgia) as a tenure-track Assistant Professor, where he is establishing an independent research program focused on T cell cross-talk in chronic inflammation and autoimmunity, using advanced in vivo and in vitro approaches including imaging, organoids, flow cytometry, and single-cell transcriptomics.
