Intranasal Inoculation of Mice with Yersinia pestis and Processing of Pulmonary Tissue for Analysis

Abstract

Pneumonic plague is a rapidly progressing and highly lethal pneumonia caused by pulmonary infection with Yersinia pestis. Disease is marked by the rapid replication of bacteria in the lungs in the absence of symptoms, followed by the abrupt onset of a highly lethal inflammatory response. A murine intranasal infection model has been key to characterizing the progression of disease. Mice are a natural Y. pestis host, and murine disease closely mirrors what is seen during human infection. Intranasal inoculation of mice with fully virulent Y. pestis strains allows for the detailed analysis of key bacterial and host factors that define disease progression. In this chapter I describe a method for intranasal inoculation of mice with Y. pestis, as well as techniques for processing lung tissue for analysis. These include protocols for isolating whole lungs and lavage fluid for measure of bacterial burden, transcriptomics, cytokine/chemokine expression, and flow cytometry. These techniques can be used to evaluate disease parameters of interest during typical infection, infection with bacterial mutants, or infection in the presence of pharmacological agents aimed at targeting specific host or bacterial factors. Combining a highly relevant murine infection model with these techniques provides a powerful platform for fully evaluating the progression of pneumonic plague.