An in vitro mononuclear cell system to model the microenvironment of coinfection with HIV-1 and Mycobacterium tuberculosis (MTB) was developed. This cellular system was used to assess the interaction of MTB-infected monocytes and T cells from dually infected HIV-1/TB patients with pulmonary tuberculosis (TB). Subjects with higher induction of HIV-1 gag/pol mRNA expression after MTB stimulation had increased MTB-specific T cell IFN-gamma and TNF-alpha production. Lack of HIV-1 mRNA induction did not correlate with increased induction of regulatory T cells (T-reg) as measured by MTB-induced Foxp3 mRNA. HIV-1 induction did not significantly correlate with clinical parameters including plasma HIV-1 viral load or CD4(+) T cell count. These data model MTB-induced HIV-1 replication at the microenvironment of MTB reactivation/infection. The data suggest that the magnitude of MTB-specific T cell responses drives local viral pathogenesis regardless of the stage of HIV-1 disease as reflected by plasma viral load or CD4(+) T cell count.