FIG. 2.

CD8⁺ T-cell activation and perforin production in response to M. bovis BCG and M. tuberculosis H37Ra. PBMC from 10 healthy BCG-vaccinated donors (solid bars) and 10 pulmonary TB patients (open bars) were incubated with M. bovis BCG, M. tuberculosis H37Ra, or medium alone (No Ag) for 7 days. CD25 expression (A) and perforin production (B) by CD8⁺ T cells were measured by two-color flow cytometry. The results are presented as the mean percentage ± the standard deviation of CD8⁺ T cells staining positive for the marker.