Figure 1.

Mycobacterial cell walls mediate the apoptosis of bone marrow macrophages. Demonstration of mycobacterial proteins in apoptotic cells. The cell wall of the transformed M. smegmatis strain (Msmeg-LpqH) expresses LpqH, the 19-kDa Mtb glycolipoprotein ((a), arrows). The native strain does not express the protein. Bone marrow MØs treated with mycobacterial cells that carry LpqH develop apoptosis, as verified by epifluorescence ((b), original 40x) and flow cytometry with FITC-labeled Annexin V (c). With staurosporine and UV, higher levels of apoptosis were observed (c). High level necrosis as revealed with propidium iodide was observed (d). Immunoblotting of mycobacteria-induced apoptotic MØs (ApopMØ-LpqH) with an anti-M. smegmatis antiserum and with a mAb revealed the presence of a few M. smegmatis antigenic bands (left) and LpqH (right). Msmeg-LpqH, protein profile of the M. smegmatis cell wall used to induce apoptosis (e). UV, ultraviolet light. We show representative results of three independent experiments.