OHSU

Dawn Nolt Lab

Background

Mycobacterium tuberculosis (Mtb), the bacterium responsible for tuberculosis (TB), infects 1/3 of the world's population and is a major cause of morbidity and mortality. The CD8+ T cell response is recognized as important in the coordinated immune response against Mtb.

Once phagocytosed by antigen-presenting cells (APCs), Mtb resides in a modified phagosome, a compartment normally associated with MHC II.  There is increasing evidence that suggests the exciting possibility that the phagosome may participate in MHC I-mediated “cross-presentation” of Mtb antigens to CD8+ T cells. Our goal is to investigate the role of phagosomes in cross-presentation during Mtb infection. 

Current projects

  • Phenotyping the phagosome with relationship to dose and duration of Mtb infection of human dendritic cells
  • Tracking the pathway of class I (particularly HLA-E, a non-classical MHC molecule) within human dendritic cells during Mtb infection
  • Understanding the role of ubiquitination in defining the trafficking destination of class I

Techniques

  • Flow cytometry and flow organellometry
  • Immunofluorescent microscopy
  • Cytokine analysis - ELISPOT
  • Western blot analysis
  • Extensive cell culturing and cloning
  • Subcellular organelle separation
  • Real-time RT PCR
  • siRNA
  • Transfections and transductions

Significance

Our long-term goal is to investigate the interaction of Mtb and CD8+ T cell immunity. Our studies will advance knowledge in key areas: 1) Mtb interactions in host cells and 2) modulation of immune function during Mtb infection. Since a future immunogenic vaccine against Mtb will likely need to incorporate CD8+ T cell responses, our findings will guide the design and development of future vaccines and therapeutics against Mtb.