T cell immunity is crucial to both controlling and preventing diseases. Currently, the most powerful way known to achieve this immunity is through the recruitment and activation of naïve T cells by professional antigen presenting cells known as dendritic cells (DCs). This activation leads to antigen-specific T cells that undergo a rapid clonal expansion after antigenic challenge. In the initial phase of this project we have optimized a culture system for the in vitro generation of DC from hematopoietic progenitor cells (HPCs).  Through a separate project, we have developed a novel, three-dimensional culture system for the production of (naïve) T cells in vitro also from HPCs.  Combined, we have developed technology to produce the cellular components required for T cell mediated immunity in vitro.  Having these two systems places us in an outstanding position to investigate the final component necessary for vaccine development using DCs:  identification of immunity-inducing antigens.

 Identification of peptides that can induce a high quality of T cell activation can be accomplished by epitope mapping. Testing overlapping synthetic peptides covering an entire sequence of an antigen has been shown to assist in the identification of immunodominant sequences that will stimulate T cells upon challenge with the intact parent protein.  This promising vaccine strategy would benefit from an assay that can quickly screen a large number of antigens for ability to produce a biologically relevant T cell response.  We propose to combine our T cell and DC production technologies to develop this assay.

• Optimize antigen presentation by in vitro produced dendritic cells (DCs)
• Optimize in vitro production of naïve T cells using artificial thymus system.
• Combine the T cell generating and DC systems to develop a high throughput in vitro assay to screen antigens, in the context of dendritic cells, for an ability to elicit T cell responses.