title: Drug-inducible, dendritic cell-based genetic immunization.
abstract: Determining the mechanism of Ag loading of Langerhans cells (LC) for genetic immunization (GI) is complicated by the inability to distinguish between the response generated by direct transfection of LC from that due to exogenous uptake. To unravel this mechanism, we examined the impact of gene gun treatment on LC with respect to their activation and migration from skin, transgene expression, and ability to initiate humoral and cellular immune responses upon transfer to naive mice. To assess responses generated by direct LC transfection, an RU486-inducible expression system was used as a GI vector. In vitro skin organ cultures were developed from gene gun immunized mouse ear specimens to obtain LC. Gene gun treatment markedly augmented (3-fold) LC migration from ear skin, and these LC expressed the transgene at RNA and protein levels. Transfer of 2 x 10(5) migratory cells resulted in identical cellular responses to, but 10-fold lower humoral responses than, standard GI. Using an RU486-inducible system, we were able to measure responses generated by directly transfected LC. Our results indicate that direct transfection is a predominant pathway for LC Ag loading. The ability to regulate transgene expression with inducible DC-based vaccines demonstrates a new level of immunological control.
authors.affiliation: Center for Biomedical Inventions, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. timares@uab.edu
authors.forename: Laura
authors.initials: L
authors.lastname: Timares
authors.forename: Karim Mahmoud
authors.initials: KM
authors.lastname: Safer
authors.forename: Baoxi
authors.initials: B
authors.lastname: Qu
authors.forename: Akira
authors.initials: A
authors.lastname: Takashima
authors.forename: Stephen Albert
authors.initials: SA
authors.lastname: Johnston
mesh_terms: D019264:Adoptive Transfer / Q000379:methods; D000818:Animals; D019470:Biolistics / Q000379:methods*; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D004423:Ear; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000276:immunology*; D006801:Humans; D007274:Injections, Intraperitoneal; D007801:Langerhans Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000637:transplantation*; D008213:Lymphocyte Activation / Q000187:drug effects / Q000235:genetics; D051379:Mice; D008805:Mice, Inbred A; D008807:Mice, Inbred BALB C; D015735:Mifepristone / Q000008:administration & dosage*; D009924:Organ Culture Techniques; D013539:Simian virus 40 / Q000235:genetics; D012867:Skin / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014161:Transduction, Genetic / Q000379:methods; D019076:Transgenes / Q000187:drug effects / Q000276:immunology; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology*; D000515:alpha 1-Antitrypsin / Q000235:genetics
chemical_list: D019444:Vaccines, DNA; D000515:alpha 1-Antitrypsin; D015735:Mifepristone