CD4 and infection: Therefore, the role of Mtb DosR-regulon encoded peptide Ag-specific single and double functional CD4+ and CD8+ T cell responses in LTBI, significantly improves the understanding of the immune response to Mtb phase-dependent Ags in the control of infection, and suggests a possible role for using MtbDosR-Ag and/or peptide based diagnostic tests or vaccination approaches to TB.