Jeffrey N. Weiser, MD

Our lab investigates the molecular basis of host–pathogen interactions in the human respiratory tract. Most of our studies focus on the pathogenesis of Streptococcus pneumoniae because of its prominence as a cause of acute respiratory tract infection. Other pathogens under investigation in our laboratory include Haemophilus influenzae, Klebsiella pneumoniae, Staphylococcus aureus, and influenza A virus.

Many of our research projects focus on colonization of the upper airway mucosa, the initial step in the disease process, with particular interest in both host and pathogen factors affecting colonization. We employ bacterial genetics to examine the effects of specific microbial genes, along with mouse models of colonization to study infection in genetically modified hosts.

Ongoing projects in our lab include examinations of the following:

• mechanisms by which colonizing microbes stimulate and evade innate and adaptive immune responses

• mechanisms that facilitate interspecies competition within a host

• factors affecting competition between co-colonizing pneumococci

• effects of influenza co-infection on bacterial colonization

• pneumococcal interaction with neutrophils and macrophages and evasion of clearance by professional phagocytes

• the role of phosphorylcholine, a surface constituent of many respiratory tract inhabitants, in pathogenesis

• host and bacterial factors affecting shedding and host-to-host transmission

• the systemic effects of colonizing flora (microbiota) on innate immunity