Phagocytosis and killing of Staphylococcus aureus by bovine neutrophils after priming by tumor necrosis factor-alpha and the des-arginine derivative of C5a.
OBJECTIVE
To evaluate effects of proinflammatory mediators on phagocytosis and killing of Staphylococcus aureus, the oxidative burst (OB), and expression of receptors for opsonins by bovine neutrophils.


METHODS
Neutrophils from 10 cattle.


METHODS
Neutrophils were primed with recombinant bovine tumor necrosis factor-alpha (TNF-alpha) or the des-arginine derivative of bovine C5a (C5a(desArg)) and mixed with S aureus. Phagocytosis and OB were measured by use of flow cytometry. Rate of phagocytosis and intracellular killing were evaluated. Expression of receptors for immunoglobulins and the C3bi fragment of complement were estimated by use of flow cytometry.


RESULTS
Priming of neutrophils by TNF-alpha improved phagocytosis of S aureus with a concentration-dependent effect. Phagocytosis of preopsonized washed bacteria was increased by activation of neutrophils with C5a(desArg). Phagocytosis was optimal when neutrophils primed with TNF-alpha were activated with C5a(desArg). The OB of phagocytizing neutrophils was highest when TNF-alpha and C5a(desArg) were used in combination. Bactericidal activity of neutrophils was stimulated by priming with TNF-alpha or C5a(desArg). Binding of bovine IgM or IgG2 to bovine neutrophils was not stimulated byTNF-alpha, C5a(desArg), or both, and aggregated IgG1 did not bind to neutrophils regardless of their activation state. Both TNF-alpha and C5a(desArg) increased expression of beta2 integrins (CD18), with the highest expression when they were used in combination.


CONCLUSIONS
The mediators TNF-alpha and C5a(desArg) stimulated phagocytic killing by neutrophils and potentiated each other when used at suboptimal concentrations. Bovine neutrophils have enhanced bactericidal activities at inflammatory sites when TNF-alpha, C5a(desArg), or both are produced locally.
Rainard
P
P
Laboratoire de Pathologie Infectieuse et Immunologie, INRA, Centre de Tours-Nouzilly, France.
Riollet
C
C
Poutrel
B
B
Paape
M J
MJ
D000818:Animals; D000911:Antibodies, Monoclonal; D018821:CD18 Antigens / Q000737:chemistry; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000382:microbiology; D015937:Complement C5a, des-Arginine / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry / Q000662:veterinary; D009504:Neutrophils / Q000382:microbiology; D010587:Phagocytosis / Q000187:drug effects* / Q000276:immunology; D017463:Receptors, Complement 3b / Q000032:analysis; D017452:Receptors, IgG / Q000032:analysis; D016897:Respiratory Burst / Q000276:immunology; D013203:Staphylococcal Infections / Q000276:immunology* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*
D000911:Antibodies, Monoclonal; D018821:CD18 Antigens; D015937:Complement C5a, des-Arginine; D017463:Receptors, Complement 3b; D017452:Receptors, IgG; D014409:Tumor Necrosis Factor-alpha