Bacterial and Host Immune Signatures during Pneumococcal Infection

The second research thrust is a recently started research program that explores how immune-cell populations in the lower respiratory tract respond differently to pneumococcal carriage versus pneumonia. In its commensal state, S. pneumoniae resides in the nasopharynx as a biofilm attached to the epithelium, causing minimal inflammation. However, when it reaches the lungs, the same organism triggers an intense and often damaging immune reaction. This project aims to map these contrasting immune landscapes using mouse models, examining the composition of immune-cell subsets, their gene-expression profiles, and the cytokine environments that distinguish benign colonization from invasive disease. By determining how the immune system tolerates pneumococcus in one site yet reacts aggressively in another, this work will help clarify what triggers disease progression. Such insights are essential for designing interventions that prevent pneumonia while respecting natural microbial carriage, and they align closely with the lab’s broad interest in immune–pathogen dynamics.