Abstract: Models for the systemic inflammatory response to infection, which involve the use of immunocompromised animals, and methods of using the models are described. These models can be used in identifying analytes or biomarker panels that can be used in staging or monitoring sepsis. The models can also be used for predicting an animal's disease outcome or in providing a prognosis for sepsis patients. Further, the invention relates to methods for evaluating potential treatments for sepsis.