PD-L1 blockade induced J-PPD-stimulated CD8<sup>+</sup> T-cell proliferation and interferon gamma production <i>in vitro</i> Combined treatment with a COX-2 inhibitor and anti-PD-L1 antibodies enhanced J-PPD-stimulated CD8<sup>+</sup> T-cell proliferation <i>in vitro</i>, suggesting that the blockade of both pathways is a potential therapeutic strategy to control Johne's disease.
The findings of this study show that IFN-γ would play a role in the development of the different types of lesions in paratuberculosis, and also points out the importance of adequate sampling of lymphoid tissue containing samples when studying the local immune response in which IFN-γ expression may be involved, especially in cases where focal lesions are present.