title: MyD88/CD40 Genetic Adjuvant Function in Cutaneous Atypical Antigen-Presenting Cells Contributes to DNA Vaccine Immunogenicity.
abstract: Therapeutic DNA-based vaccines aim to prime an adaptive host immune response against tumor-associated antigens, eliminating cancer cells primarily through CD8+ cytotoxic T cell-mediated destruction. To be optimally effective, immunological adjuvants are required for the activation of tumor-specific CD8+ T cells responses by DNA vaccination. Here, we describe enhanced anti-tumor efficacy of an in vivo electroporation-delivered DNA vaccine by inclusion of a genetically encoded chimeric MyD88/CD40 (MC) adjuvant, which integrates both innate and adaptive immune signaling pathways. When incorporated into a DNA vaccine, signaling by the MC adjuvant increased antigen-specific CD8+ T cells and promoted elimination of pre-established tumors. Interestingly, MC-enhanced vaccine efficacy did not require direct-expression of either antigen or adjuvant by local antigen-presenting cells, but rather our data supports a key role for MC function in "atypical" antigen-presenting cells of skin. In particular, MC adjuvant-modified keratinocytes increased inflammatory cytokine secretion, upregulated surface MHC class I, and were able to increase in vitro and in vivo priming of antigen-specific CD8+ T cells. Furthermore, in the absence of critical CD8α+/CD103+ cross-priming dendritic cells, MC was still able to promote immune priming in vivo, albeit at a reduced level. Altogether, our data support a mechanism by which MC signaling activates an inflammatory phenotype in atypical antigen-presenting cells within the cutaneous vaccination site, leading to an enhanced CD8+ T cell response against DNA vaccine-encoded antigens, through both CD8α+/CD103+ dendritic cell-dependent and independent pathways.
authors.affiliation: Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, United States of America.|Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States of America.
authors.forename: Matthew R
authors.identifier: http://orcid.org/0000-0003-2756-7309
authors.initials: MR
authors.lastname: Collinson-Pautz
authors.affiliation: Bellicum Pharmaceuticals, Houston, TX, United States of America.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Slawin
authors.affiliation: Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, United States of America.|Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States of America.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Levitt
authors.affiliation: Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States of America.|Bellicum Pharmaceuticals, Houston, TX, United States of America.
authors.forename: David M
authors.initials: DM
authors.lastname: Spencer
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D019013:CD40 Antigens / Q000235:genetics*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D019496:Cancer Vaccines / Q000276:immunology / Q000627:therapeutic use; D002460:Cell Line; D049109:Cell Proliferation; D016207:Cytokines / Q000032:analysis / Q000378:metabolism; D005260:Female; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics*; D041681:NIH 3T3 Cells; D009369:Neoplasms / Q000276:immunology / Q000628:therapy; D019444:Vaccines, DNA / Q000276:immunology* / Q000627:therapeutic use
chemical_list: D019013:CD40 Antigens; D019496:Cancer Vaccines; D016207:Cytokines; D035683:MicroRNAs; D053594:Myeloid Differentiation Factor 88; D019444:Vaccines, DNA