Gregory Donaldson

Gregory Donaldson is an Assistant Professor in the Department of Microbiology, Immunology, and Molecular Genetics (MIMG) at the David Geffen School of Medicine, UCLA. His research focuses on understanding how gut microbiota interact with the host immune system and influence health, particularly in contexts such as cancer, neuroregeneration, and mucosal immunity.

His work spans microbiology, immunology, and gastroenterology, with a strong emphasis on animal models to study microbial colonization, bacterial metabolites, and host responses. Notable contributions include discoveries about immunoglobulin A’s role in tumor suppression, microbiota-driven serotonin regulation, and the spatial ecology of Bacteroides fragilis in the colon.

Publications highlight interdisciplinary approaches, combining microbiology with systems biology and immunology to address questions in host-microbiota symbiosis. Key themes include microbial utilization of host immune components, gut-brain axis interactions, and the dynamics of B cell responses in the gut.

His research has been published in top journals like Nature, Science, and Cell, with over 1,400 citations for his 2015 Cell paper on serotonin regulation. Collaborations include work with co-authors like Sarkis K. Mazmanian, Gabriel D. Victora, and Elaine Y. Hsiao.