Immunization with vaccinia virus resulted in long-lasting protection against smallpox and was theapproach used to eliminate natural smallpox infections worldwide. This was accomplished without a detailedunderstanding of human T cell responses to poxviruses. Due to concerns about the use of smallpox virus asa bioweapon, smallpox vaccination is currently being reintroduced. Considering the relatively high incidenceof side effects, developing a safer, but effective vaccine is very important.Vaccinia virus elicits strong cellular as well as humoral immune responses. Cellular immunity seemsto be more important for recovery from infection. Severe complications from vaccination were associatedwith congenital or acquired T cell deficiencies, but not with congenital agammaglobulinemia. The presenceof neutralizing antibody alone did not prevent the development of progressive vaccinia if cell-mediatedimmunity was defective. In order to analyze human T cell responses to licensed and experimental smallpoxvaccines at the single cell level, it is essential to identify T cell epitopes, especially immunodominant CD8 Tcell epitopes.Vaccinia is a large virus and we hypothesize that we can develop a rapid approach to localize genefragments encoding human T cell epitopes and to identify them precisely using peptides using PCRgeneratedDNA fragments containing virus genes transfected into antigen presenting cells. Complementarystrategies will employ peptide libraries and studies in transgenic mice expressing common human MHCclass I molecules. The immunodominance of human T cell epitopes on vaccinia virus will be analyzed. Theresults of this research project will provide valuable information relative to basic studies of human T cellmemory and data useful for the design and analyses of experimental smallpox vaccines. The methods wewill establish in this project may be applicable to other large viruses as well as bacteria for the definition ofhuman T cell epitopes.
Showing the most recent 10 out of 109 publications
