Lentivirally generated eGFP-transgenic rats allow efficient cell tracking in vivo

Here we describe the efficient generation of eGFP-transgenic rats using a lentiviral approach. Analysis of the founder generation demonstrated that 46% of the offspring had stably integrated the provirus into the genome and of those 92% expressed eGFP in all blood-derived leukocytes. In contrast to their offspring, all founder rats were mosaic with regard to eGFP-expression, suggesting delayed viral transduction after injection. The expression level of eGFP in the F1 generation is influenced by and segregates with the site of proviral integration. Interestingly, a single copy of the transgene is sufficient for reliable detection by flow cytometry, irrespective of the leukocyte subtype analyzed. Adoptive transfer of purified CD4(+) T-lymphocytes from transgenic rats and subsequent reisolation from various organs further demonstrated that expression of the lentiviral transgene is maintained in a foreign host and therefore allows for efficient tracking of transferred cells. Taken together, lentivirally generated eGFP-transgenic rats are a powerful tool for various applications in immunology and presumably also many other fields.