Life Sciences Commons^™

Identification Of The Role Of The Sal Locus In Streptococcus Pyogenes Virulence During Host-Pathogen Interactions, Phanramphoei Namprachan-Frantz

Wayne State University Dissertations

The pathogenesis of Streptococcus pyogenes is due to its ability to overcome and adapt to the harsh environment created by the host immune response. The focus of this project was the SalKR two-component regulatory system, which facilitates bacterial adaptation by responding to environmental signals during host pathogen-interactions. The first goal of this project was to determine a role in virulence for the SalKR regulatory system. The complete deletion of the salKR genes in the wild type S. pyogenes strain HSC5 produced a highly attenuated mutant in a Zebrafish infection model. The ΔsalKR mutant appeared to lose the ability to survive …

Ctla-4 Transcriptional Activation: Regulation Of Induced Expression, Heather Gibson

Wayne State University Dissertations

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a T cell surface protein that is homologous to CD28 and binds to the B7 family of ligands. Unlike CD28, CTLA-4 interaction transmits a negative signal in T cells, leading to suppression of proliferation. CTLA-4 is constitutively expressed on regulatory T cells (Tregs) but is also inducible in effector T cells. The mechanisms driving transcriptional regulation of CTLA-4 are poorly understood. Our previous work identified a bona fide NFAT1 binding site in the proximal promoter for effector T cells. In addition, we found histone acetylation occurred after stimulation.

As a result of its role …

Analysis Of The Streptococcal Cpsa Protein In Dna-Binding And Regulation Of Capsule And Cell Wall Maintenance, Brett R. Hanson

Wayne State University Dissertations

The systemic pathogens Streptococcus agalactiae (GBS) and Streptococcus pneumoniae remain a significant threat to human health worldwide. The ability of these organisms to cause systemic disease is compounded by the production of a polysaccharide capsule that provides immune evasion function. The production of the polysaccharide capsule in systemic streptococcal pathogens is controlled in part by the membrane bound protein CpsA. These studies analyze the contribution of CpsA to regulation of capsule level in the model aquatic pathogen Streptococcus iniae and human specific pathogen GBS, and how this regulation affects virulence in in-vitro, ex-vivo, and in-vivo models of pathogenesis. We have …