Secretion of cytokines by human macrophages upon infection by pathogenic and non-pathogenic mycobacteria.
The interaction of various pathogenic (Mycobacterium tuberculosis, M. avium, M. kansasii, M. xenopi), and non-pathogenic mycobacteria (M. smegmatis, M. phlei) with human macrophages at the level of macrophage cytokine expression (TNFalpha, IL1, IL6 and GM-CSF) was investigated. Both for TNFalpha and GM-CSF, the lowest levels were obtained with pathogenic mycobacterial species, whereas about 2-8 times higher levels were observed for non-pathogenic species. Contrary to the above, the differences for IL6 and IL1 were not marked, although IL6 appeared to be more elevated for non-pathogenic species. Heat-killed bacteria induced a lower level of the cytokines for all the three cytokines assayed (TNFalpha, IL6 and IL1), except for M. tuberculosis for whom a significantly higher proportion of TNFalpha was induced by killed bacilli. The RT-PCR experiments performed on M. avium (as a low inducer of the cytokines) and M. smegmatis (as a high inducer of the cytokines) showed that the differences observed among pathogenic vs non-pathogenic strains were also reflected at the transcriptional level for TNFalpha and to a lesser extent for IL6, but not for IL1. This investigation underlined important differences existing between the pathogenic and non-pathogenic species, particularly as regards TNFalpha and GM-CSF.
Beltan
E
E
Unité de la Tuberculose et des Mycobactéries, Institut Pasteur, Morne Jolivière, BP 484, Pointe-à-Pitre, 97165, Guadeloupe.
Horgen
L
L
Rastogi
N
N
D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D006361:Heating; D006801:Humans; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism* / Q000382:microbiology; D009161:Mycobacterium / Q000378:metabolism* / Q000472:pathogenicity; D009164:Mycobacterium Infections / Q000378:metabolism* / Q000382:microbiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014774:Virulence
D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor