Lysis of human macrophages by cytolytic CD4+ T cells fails to affect survival of intracellular Mycobacterium bovis‐bacille Calmette‐Guérin (BCG)

• Published in: Clinical and experimental immunology 1995-01, Vol.99 (1), p.82-89
• Main Authors: FAZAL, N., LAMMAS, D. A., RAHELU, M., PITHIE, A. D., GASTON, J. S. H., KUMARARATNE, D. S.
• Format: Article
• Language: English
• Subjects: Bacteriology; Biological and medical sciences; CD4; CD4-Positive T-Lymphocytes - cytology; CD4-Positive T-Lymphocytes - immunology; Cells, Cultured; Clone Cells; cytolytic T cells; Cytotoxicity, Immunologic; Fundamental and applied biological sciences. Psychology; human macrophages; Humans; intracellular survival; Macrophages - cytology; Macrophages - immunology; Microbiology; mycobacteria; Mycobacterium bovis - growth & development; Mycobacterium bovis - immunology; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains
• ISSN: 0009-9104; 1365-2249
• DOI: 10.1111/j.1365-2249.1995.tb03476.x

SUMMARY Human CD4+, mycobacteria‐specific, cytolytic T cell clones were used to lyse BCG‐infected macrophages. and the effect on the subsequent growth and viability of the organisms was examined. The survival of released bacteria following cell lysis was assessed by both 3H‐uridine labelling and colony‐forming unit (CFU) estimation. The results indicate that even when effective antigen‐specific or lectin‐mediated cytolysis of the infected macrophages was achieved, there was no evidence for a direct mycobactericidal effect on the intracellular bacteria. This remained the case even if the period of co‐culture of T cells and macrophages was extended up to 48 h. Pretreatment of the macrophages with interferon‐gamma (IFN‐γ) was not able to act together with T cell‐mediated lysis to produce inhibition of mycobacterial growth.