Joseph W. St. Geme III, M.D.
Dr. St. Geme’s research interests are in host-pathogen interactions and is using genetic methods,. My laboratory is interested in host-pathogen interactions and is using genetic methods, protein chemistry, X-ray crystallography, high resolution microscopy, and microarray analysis to study the molecular and cellular determinants of disease due to Haemophilus influenzae, a model mucosal pathogen and a common cause of local respiratory tract disease and serious invasive infection. H. influenzae expresses a number of adhesive proteins that mediate interaction with host epithelium, and we are studying the biogenesis, adhesive specificity, and regulation of these proteins. H. influenzae is also capable of entering and surviving inside host cells, a strategy that may have evolved to provide the organism with a protected niche. In ongoing work, we are examining the host cell receptors, cytoskeletal elements, and signaling molecules involved in cellular entry. Recent evidence indicates that H. influenzae forms biofilms, complex communities of organisms that likely facilitate persistence on the respiratory epithelial surface. We are seeking to understand the bacterial and host factors that influence H. influenzae biofilm formation, and we are beginning to study the relationship between biofilms and evasion of innate immune mechanisms, such as cationic peptides, lactoferrin, and phagocytosis. Using H. influenzae and human DNA microarrays, we hope to uncover novel pathways that are fundamental to the outcome of encounters between bacteria and the human host.
From a practical perspective, his lab’s work has relevance to development of novel antimicrobial compounds and to generation of a vaccine broadly effective against H. influenzae.