The effects of live Neisseria meningitidis and tumour necrosis factor‐α on neutrophil oxidative burst and β2‐integrin expression

Abstract

The effects of human recombinant tumour necrosis factor-alpha (TNF-alpha) on neutrophil (PMNL) oxidative burst and on CD11b/CD18 and CD14 expression after stimulation with pathogenic or nonpathogenic Neisseria meningitidis were studied using chemiluminescence and flow cytometry. PMNL oxidative burst increased more when stimulated with the apathogenic 29E strain than with the pathogenic B strain both when studied by chemiluminescence and by flow cytometry. When TNF-alpha was added to whole blood or PMNL together with bacteria a significant increase in the oxidative burst was seen for the B strain only. When whole blood was preincubated for 30 min with TNF-alpha the increase in oxidative burst was significant for both meningococcal strains. TNF-alpha caused a significant increase in PMNL CD 11b/CD18 expression after 30 min of incubation at 37 degrees C. TNF-alpha added simultaneously with the bacteria induced a significant increase in PMNL CD11b/CD18 in both strains. Incubation with the B strain alone caused a low but significant increase in CD11b/CD18 expression, but the addition of TNF-alpha increased this expression to the same high level as incubation with TNF-alpha alone or the 29E strain alone. Only TNF-alpha and the 29E strain caused significant increases in CD14 expression. In conclusion, human PMNLs react differentially when stimulated with pathogenic and nonpathogenic N. meningitidis and the activating effect of TNF-alpha is variable depending on the bacteria involved.

Outer membrane vesicles from Neisseria meningitidis

“…The downregulation of leukocyte CD62L and the simultaneous upregulation of b 2 integrins which occured upon challenge with OMV-LPS is in accordance with results obtained by other groups performing experiments with strains of live N. meningitidis in whole blood models of meningococcal bacteremia (30,37,38). Morever, the described modulation of the leukocyte adhesion molecule profile appears to represent prototypical changes which are a prerequisite for triggering the classical chain of events, including leukocyte rolling, arrest, firm adhesion and transendothelial migration.…”

The role of complement receptor 3 (CR3) inNeisseria gonorrhoeaeinfection of human cervical epithelia

“…Upregulation of CD11b in neutrophils has been documented in response to Neisseria meningitidis infection (Kragsbjerg et al, 2000). The direct association of CR3 with pathogenic Neisseria, however, has not been demonstrated.…”

Activation of granulocytes in patients treated with chemotherapy

“…One Staphylococcus epidermidis strain and one Staphylococcus aureus strain from our strain collection were used as activators. The bacterial concentration was adjusted to a ratio of one bacterial cell to one granulocyte, which previously has been shown to give signi®cant results (Kragsbjerg, Fogelqvist & Fredlund, 2000;Kragsbjerg & Fredlund, 2001). Each sample was divided into two tubes; one was analysed immediately after the addition of bacteria and the other after incubation for 30 min.…”