Jeffrey N. Weiser M.D.

Professor of Pediatrics and Microbiology

Department of Microbiology
Perelman School of Medicine
University of Pennsylvania
402A Johnson Pavilion
3610 Hamilton Walk
Philadelphia, PA 19104-6076

TEL 215-573-3511
LAB 215-573-3510
FAX 215-573-4856
weiser@mail.med.upenn.edu

SUMMARY OF RESEARCH

The Weiser lab investigates the molecular basis of host-pathogen interaction for bacteria that reside in and infect the human respiratory tract. Most 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 the laboratory include Haemophilus influenzae, Klebsiella pneumoniae and Staphylococcus aureus. Many projects focus on colonization of the mucosal surface of the upper airway, the initial step in the disease process. Both host and bacterial factors affecting colonization are under investigation. In general these studies utilize bacterial genetics to examine effects of specific microbial genes together with mouse models of colonization that allow for the use of genetically-modified hosts.

On-going projects examine:

• How colonizing microbes stimulate and evade innate immune clearance mechanisms.
• How the cellular immune responses acts to clear pneumococcal colonization.
• Mechanisms that facilitate interspecies competition within a host.
• Mechanisms of competition between co-colonizing pneumococci.
• Pneumococcal interactions with neutrophils and mechanisms to evade killing by professional phagocytes.
• The host-microbe battle for acquisition of iron on the mucosal surface and its implications for inflammation.
• The potential of live attenuated vaccines that colonize and induce protective immunity but are avirulent
• The role of phosphorycholine, a surface constituent of many respiratory tract pathogens, in pathogenesis.
• Bacterial surface components that undergo phase variation in their expression as a mechanism of adaptation.