We showed recently that a rationally designed adenovirus-based vaccine could confer a high level of protection from FV challenge infection similar to the gold standard, attenuated anti-FV vaccine F-MuLV-N, albeit by different mechanisms [9]; indeed the DNA-based, cytokine-adjuvanted vaccine that we present here proves similarly effective, and furthermore might be applicable as a therapeutic vaccine as induction of CD8+ T cell responses does not rely on the vaccinee being envelope naïve. The gene discussed is CD8A; the disease is infection.