- Assistant Professor, Department of Immunobiology, Yale School of Medicine, Yale University
Dr. Esen Sefik is an Assistant Professor in the Department of Immunobiology at Yale School of Medicine. She received her BS from Yale College and her PhD from Harvard University.
During her doctoral training, Dr. Sefik explored host-microbe interactions from a tolerogenic perspective, focusing on tissue-level immune homeostasis. She conducted a pioneering large-scale screen colonizing germ-free mice with individual bacterial strains, uncovering microbiota-dependent transcriptional control mechanisms governing Foxp3+ regulatory T cells and IL-17-producing T cells. Her findings suggested a collaborative rather than competitive regulation between Rorγ and Foxp3, facilitated by the microbiota.
During her postdoctoral training, Dr. Sefik used humanized mice to model human-microbe interactions in chronic infectious and inflammatory diseases. She developed a humanized mouse model of severe COVID-19 that exhibited persistent lung pathology mirroring that seen in human patients, revealing the unique contributions of human macrophages to lung pathology. These models have also proven valuable for studying fibrotic diseases with microbial etiology.
Dr. Sefik’s laboratory investigates how the complex system of immune and non-immune cell interactions in tissues breaks down during chronic infection. Her work emphasizes the delicate balance maintained by host-microbe interactions — critical for immune development yet vulnerable to chronic inflammatory stimuli — with the long-term goal of translating mechanistic discoveries into therapeutic advancements.