New research published in Immunity describes a standardized method to reproducibly measure a functional immune response in healthy donors. Conducted by researchers at the Institut Pasteur, the study defines protein signatures of the healthy immune response to several relevant stimuli, including common pathogenic microorganisms, defined host sensor agonists, clinically employed cytokines, and activators of T-cell immunity. The research promises to help scientists understand and better predict immune response, in addition to informing therapeutic intervention.