Rv3881c from Mycobacterium tuberculosis Elicits PolyFunctional CD8+ T cells in PPD Positive Healthy Volunteers and Affords Significant Protection in the Guinea Pig Model

We show that Rv3881c, a secreted protein of M. tuberculosis (MTB), elicits T cell responses from healthy PPD-positive individuals and TB patients. Synthetic peptides spanning the complete length of Rv3881c induced secretion of significantly greater levels of TNF-α and IL-10 from peripheral blood mononuclear cells of TB patients compared to latently infect healthy volunteers. Polychromatic flow cytometry detected poly-functional CD4+ and CD8+ T cells secreting different combinations of IFN-γ, TNF-α, IL-2 and MIP-1β in response to Rv3881c. Levels of CD4+ T cells secreting either IFN-γ or TNF-α were significantly higher in TB patients while levels of CD8+ T cells secreting both IFN-γ and IL-2 were significantly greater in healthy PPD-positive volunteers.