Research Abstracts Online
2008 - March 2009
University of Minnesota Twin Cities
Department of Microbiology
PI: P. Patrick Cleary
Co-PI: Beinan Wang
Innate Immune Response to Streptococcus pyogenes Infection in Nasal-associated Lymphoid Tissue; Domain Mapping of SPCA
The Cleary laboratory is involved in two projects that investigate Streptococcus pyogenes, which causes pharyngitis in children and adults as well as sequelae such as rheumatic fever and streptococcal toxic shock syndrome. S. pyogenes uses several mechanisms to avoid early host defenses. M proteins are fibronectin- and laminin-binding proteins that promote invasion of streptococci into epithelial cells. M proteins also interfere with deposition of C3b opsonin and activation of the alternative complement pathway. Streptococci produce a serine protease called streptococcal C5a peptidase (SCPA) that cleaves C5a, a complement protein. C5a is critical chemotaxin for many types of cells, including macrophages and neutrophils.
The first project investigates the early response to S. pyogenes of the nasal-associated lymphoid tissue and to evaluate whether this response is influenced by streptococcal virulence factors M protein and SCPA. The second project, begun during this period, investigates the structure-function relationship of different domains of SCPA by cloning and expressing them as histidine-tagged proteins in Escherichia coli.
Dileepan Thamotharampillai, Staff