The present invention provides for novel compositions and methods for delivering genes of interest to stem cells using vectors that contain differentiation-specific transcriptional regulatory elements. For example, stem cells in the internal epithelia could be transfected with a vaccine construct, which has an epithelial cell differentiation-specific promoter driving the expression of viral envelope proteins. When the promoter used is specific for terminally differentiated epithelial cells, then the viral envelope proteins will be expressed only in the upper part of the epithelia and therefore, stimulate the immune response. The infected epithelial stem cells in the basal layer will continue to produce new antigen-expressing cells, without being eliminated by the immune response. This invention will be useful in the development of vaccines against viral agents that target the internal mucosa like HIV.
