Interferon γ (IFN-γ)-producing TB antigen-specific CD4+ effector T cells and memory T cells can be monitored by an enzyme-linked immunospot assay (ELISPOT) [25], in which galectin-9–CD44 interaction enhances stability and function of adaptive regulatory T cells (Tregs), promoting Foxp3 expression and, therefore, suppressing effector T cell responses during infection [26]. This evidence concerns the gene CD44 and tuberculosis.