Janelle S. Ayres is an American immunologist and microbiologist, member of the NOMIS Center for Immunobiology and Microbial Pathogenesis and Helen McLoraine Developmental Chair at the Salk Institute for Biological Sciences.

[2] Ayres received her BA in molecular and cell biology at the University of California, Berkeley and her PhD at Stanford University School of Medicine in the laboratory of David Schneider, working on resistance and infection tolerance using the model organism Drosophila.

[3][4] She then completed a postdoctoral fellowship with Russell Vance at the University of California, Berkeley where she published on the role of innate immunity in the recognition of drug resistant pathobionts, or potentially virulent species from the microbiome.

[5] Ayres current research focuses on how microbes can promote the health of their host organism.

She uses mathematical and evolutionary models to predict how the beneficial microbes in the gut can be used to fight diseases.