Tumor necrosis factor alpha stimulates killing of Mycobacterium tuberculosis by human neutrophils.
The ability of human neutrophils to aid in defense against pulmonary infection with Mycobacterium tuberculosis is controversial. In this study, we have shown that neutrophils respond to and phagocytose M. tuberculosis in human lesions. Neutrophils from healthy individuals were able to kill significant fractions of an inoculum of M. tuberculosis within 1 h of phagocytosis, and this ability was enhanced by tumor necrosis factor alpha but not by gamma interferon. The mycobactericidal mechanism was nonoxidative, as inhibitors of reactive oxygen or reactive nitrogen intermediates did not interfere with killing. However, the mycobactericidal mechanism was associated with increased exposure of intracellular M. tuberculosis to neutrophil defensins. In vitro, human neutrophil peptides 1 to 3 were not able to kill the bacilli even at much higher levels. These studies support the concept that human neutrophils are directly involved in defense against infection with M. tuberculosis.
Kisich
Kevin O
KO
Department of Immunology, National Jewish Medical and Research Center, Denver, Colorado 80206, USA. kisichk@njc.org
Higgins
Michael
M
Diamond
Gill
G
Heifets
Leonid
L
D017209:Apoptosis; D002478:Cells, Cultured; D006801:Humans; D007424:Intracellular Fluid / Q000382:microbiology; D009169:Mycobacterium tuberculosis / Q000254:growth & development / Q000276:immunology*; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology; D010587:Phagocytosis / Q000187:drug effects* / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D023084:alpha-Defensins / Q000276:immunology
D014409:Tumor Necrosis Factor-alpha; D023084:alpha-Defensins; C406413:human neutrophil peptide 1; C406416:human neutrophil peptide 2; C406427:human neutrophil peptide 3