LYSIS OF HUMAN MACROPHAGES BY CYTOLYTIC CD4(-CELLS FAILS TO AFFECT SURVIVAL OF INTRACELLULAR MYCOBACTERIUM-BOVIS BACILLE CALMETTE-GUERIN (BCG)() T)

Human CD4(+), mycobacteria-specific, cytolytic T cell clones were used to lyse BCG-infected macrophages, and the effect on the subsequent gr owth and viability of the organisms was examined. The survival of rele ased bacteria following cell lysis was assessed by both H-3-uridine la belling and colony-forming unit (CFU) estimation. The results indicate that even when effective antigen-specific or lectin-mediated cytolysi s of the infected macrophages was achieved, there was no evidence for a direct mycobactericidal effect on the intracellular bacteria. This r emained the case even if the period of co-culture of T cells and macro phages was extended up to 48 h. Pretreatment of the macrophages with i nterferon-gamma (IFN-gamma) was not able to act together with T cell-m ediated lysis to produce inhibition of mycobacterial growth.