Although the ability of RhCMV/TB vectors to protect against TB challenge was maintained with this gene-repair and response reversion, the efficacy of RhCMV/SIV vectors against SIV challenge was abrogated, suggesting the unconventionally restricted CD8+ T cells play a critical role in the ability of RhCMV/SIV vector-elicited responses to control SIV challenge. The gene discussed is CD8A; the disease is tuberculosis.