Ex vivo platforms were developed to study the functional activity of effector T cells proliferating in response to candidate vaccine antigens, processed and presented by monocyte derived dendritic cells (MoDC). PBMC from a steer vaccinated with a Mycobacterium paratuberculosis (Map) deletion mutant (Map/relA) were used to demonstrate the potential of the platforms to study the effector T cell response to a live vaccine and a candidate Map major membrane protein (MMP). MoDC pulsed with Map/relA were shown to elicit CD4 and CD8 T cell memory recall responses. An identical response was obtained with MoDC pulsed with MMP, showing a major component of the response to Map/relA was against MMP. Further evaluation of the functional activity of memory T cells responding to Map/relA and MMP stimulation showed they were able to kill intracellular bacteria in cultures of macrophages infected with Map. The MoDC and infected target cell platforms obviate many of the difficulties in assessing the potential efficacy of vaccines in outbred species before testing in the field. RNAseq can be used to evaluate signaling in MoDC mediated by different constructs of candidate vaccines. RNAseq can also be used to monitor signaling mediated by antigen-pulsed MoDC, associated with modulating differentiation of T cells with different functional activity. The ex vivo target cell platform can be designed, as needed, to evaluate effector T-cell activity.