Enhancement of polymorphonuclear cell phagocytosis by lipid A-activated monocytes via cell-to-cell contact: a possible role for membrane-associated interleukin-6 and interleukin-8.
Polymorphs (PMN) and monocytes/macrophages (Mo) play a very important role in the host defence since they participate to inflammatory processes, tissue repairing and antitumor activity. Previous studies showed that lipopolysaccharide (LPS)-activated Mo are able to upregulate PMN phagocytic ability via cell-to-cell contact mechanisms mediated by bound to Mo membrane (m) cytokines (CKs), such as Tumor Necrosis Factor (TNF)-alpha, Interleukin (IL)-1 alpha and IL-1 beta. Based on these grounds, the role of Mo m-associated IL-6 and IL-8 on the modulation of PMN activity has been evaluated. In the first step, PMN incubated with lipid A (LA)-activated Mo showed an increased phagocytosis dependent on cell-to-cell contact only. In the second step, LA-activated Mo were pretreated with antirecombinant human (Rhu) IL-6 and IL-8 monoclonal antibodies (MoAbs), respectively and, in such a way, the enhanced phagocytic activity of PMN was abrogated. In the third step, PMN incubated with LA-activated supernatants (AS) from PBMC cultures exhibited an enhanced phagocytic activity, that was abrogated when LA-AS were pretreated with anti-Rhu IL-6 and anti-Rhu IL-8 MoAbs, respectively. These data suggest that IL-6 and IL-8 associated to Mo membrane may modulate PMN activation through a cell-to-cell contact dependent pathway.
Decandia
P
P
University of Bari Medical Faculty, Policlinico, Italy.
Serrone
M
M
Pestillo
L
L
Ribaud
M R
MR
De Simone
C
C
Tortorella
C
C
Antonaci
S
S
Jirillo
E
E
D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology; D001667:Binding, Competitive / Q000276:immunology; D002448:Cell Adhesion / Q000276:immunology*; D006801:Humans; D015850:Interleukin-6 / Q000276:immunology; D016209:Interleukin-8 / Q000276:immunology; D008050:Lipid A / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology*; D010587:Phagocytosis / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology
D000911:Antibodies, Monoclonal; D015850:Interleukin-6; D016209:Interleukin-8; D008050:Lipid A; D011994:Recombinant Proteins