title: Efficient priming of CD4+ and CD8+ T cells by DNA vaccination depends on appropriate targeting of sufficient levels of immunologically relevant antigen to appropriate processing pathways.
abstract: The initial cellular events and interactions that occur following DNA immunization are likely to be key to determining the character and magnitude of the resulting immune response, and as such, a better understanding of these events could ultimately lead to the design of more effective pathogen-appropriate DNA vaccines. Therefore, we have used a variety of sensitive cell-based techniques to study the induction of adaptive immunity in vivo. We examined the efficacy of induction of Ag-specific CD4(+) and CD8(+) T cell responses in vivo by the adoptive transfer of fluorescently labeled Ag-specific TCR transgenic T cells and have demonstrated how such approaches can be used to study the effect of simple DNA construct manipulations on immunological priming. OVA-specific CD8(+) and CD4(+) T cells were activated and divided in vivo following immunization with DNA constructs that targeted OVA expression to different subcellular locations; however, the kinetics and degree of cell proliferation were dependent on the cellular location of the expressed protein. DNA vectors encoding cell-associated OVA resulted in greater CD8(+) T cell division compared with other forms of OVA. In contrast, soluble secreted OVA targeted to the classical secretory pathway enhanced division of CD4(+) T cells. Furthermore, the inclusion of mammalian introns to enhance protein expression increased the ability of poorly immunogenic forms of Ag to activate naive T cells, indicating that not only the location, but also the amount of Ag expression, is important for efficient T cell priming following DNA injection.
authors.affiliation: Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, United Kingdom. C.Rush@bio.gla.ac.uk
authors.forename: Catherine
authors.initials: C
authors.lastname: Rush
authors.forename: Tim
authors.initials: T
authors.lastname: Mitchell
authors.forename: Paul
authors.initials: P
authors.lastname: Garside
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000235:genetics; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D019556:COS Cells; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D002999:Clone Cells; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006801:Humans; D006825:Hybridomas / Q000276:immunology / Q000378:metabolism; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000097:blood; D007156:Immunologic Memory / Q000235:genetics; D007273:Injections, Intramuscular; D007371:Interferon-gamma / Q000096:biosynthesis; D007438:Introns / Q000235:genetics / Q000276:immunology; D008213:Lymphocyte Activation / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009928:Organ Specificity / Q000235:genetics / Q000276:immunology; D010047:Ovalbumin / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010957:Plasmids / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D014162:Transfection; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D007074:Immunoglobulin G; D011993:Recombinant Fusion Proteins; D019444:Vaccines, DNA; D007371:Interferon-gamma; D010047:Ovalbumin