Abstract: Adoptive immunotherapy is finding an increasingly important role in fighting cancer. However, in order for T cells to mediate any effective response large numbers of T cells must be transferred into patients. Current culture techniques used to expand T cells can have an adverse affect on their function and ability to localize to tumor sites. In order to address this problem researchers are developing better culture systems and ways to better target cells to tumor. These changes have created a need to not only non-invasively monitor locations of these cells but determine if the cell is functional in vivo as it is in cell culture. To this end we have developed strategies to monitor T cell function in vivo by linking a reporter gene to promoters that drive expression of T cell activation markers (e.g. Granzyme B). However, these promoters are relatively weak in terms of driving the expression of enough reporter protein to lead to enough imaging signal to be detected from living animals. Therefore we hypothesized that by boosting the signal from these promoters we would be able to detect signals in living animals. We used two methods to increase the signal, the Two Step Transcription Amplification (TSTA) system, developed at UCLA, and the CMV enhancer (CMVe). Both strategies in a lentivrial setting successfully increased Granzyme B promoter activity in primary murine splenocytes. However, both the level activity and titer of lentivirus using the CMVe was significantly higher than TSTA. Using Listeria monocytogenes infection as our model we were able to visualize T cell activation from adoptively transferred transduced T cells in the spleen and liver of infected mice. Using this vector we will be able to visualize T cell activation in an adoptive immunotherapy model for tumor treatment.