Functional characteristics of neutrophils and mononuclear cells from tuberculosis patients stimulated in vitro with heat killed M. tuberculosis.
BACKGROUND
The major protective immune response against intracellular bacteria, such as Mycobacterium tuberculosis, is a cell-mediated immunity involving neutrophils (PMNs) and peripheral mononuclear cells (MCs), contributing to the clearance of this microorganism and the resolution of the infection. This study was addressed to evaluate PMNs and MCs for their bactericidal function.


METHODS
The sample comprised 14 tuberculosis (TB) inpatients (HIV-), and 10 healthy controls (HCo). Peripheral PMNs and MCs were separated by Ficoll-Hypaque and cultured in RPMI with or without heat-killed Mycobacterium tuberculosis (HK Mtb). Respiratory burst (RB), CD11b, IL-8 and TNFalpha receptor expression were assessed by flow cytometry in cells undergoing stimulation or not. Presence of IL-8 and TNFalpha in cell culture supernatants was determined by ELISA.


RESULTS
TB patients had a lower RB response than HCo for both cell types (MCs, p <0.05, PMNs, p <0.01) regardless of HK Mtb stimulation. Compared to HCo, PMNs and MCs from TB patients presented a reduced CD11b expression, with the two subject groups showing a decrease in this marker expression following HK. Mtb was added to both cell cultures. Whereas fewer IL-8 and TNFalpha receptors were found when studying MCs and PMNs from TB patients, antigen stimulation significantly raised the expression for both cytokine receptors. Culture supernatants from MCs and PMNs of TB patients contained increased amounts of IL-8 and TNFalpha.


CONCLUSIONS
The present findings may provide some explanation as to the different roles played by PMNs and MCs in TB immunopathology.
Fiorenza
Gladys
G
Sección Inmunología, Cátedra de Microbiología. Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina.
Farroni
Miguel A
MA
Bogué
Cristina
C
Selenscig
Dante
D
Lamas
Diego Martinel
DM
Dlugovitzky
Diana
D
D000328:Adult; D016207:Cytokines / Q000276:immunology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology* / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology; D018375:Neutrophil Activation; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism; D016897:Respiratory Burst; D014376:Tuberculosis / Q000097:blood / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology
D016207:Cytokines