CD4 and Granuloma: Using these new tetramers, plus two tetramers that had previously been developed to identify CD4 T cells that were specific for CFP-10, we investigated Mtb-specific T cells within infected MCMs, thereby providing insight into the presence of Mtb-specific T cells in the blood, BAL, lungs, lung granulomas, lymph nodes (LNs), and extrapulmonary sites (EP) (3).