Enhancement of polymorphonuclear cell phagocytosis by lipid A-activated monocytes via cell-to-cell contact. A possible role for membrane-associated cytokines.
Previous findings have shown that lipopolysaccharide (LPS)-activated human monocytes express cytokines (CKs) on their membrane. Furthermore, those associated to membrane products such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 have been demonstrated to exert many biological activities. In this paper, evidence is provided that human polymorphonuclear cells (PMN) exhibited an increased phagocytic capacity following incubation with either lipid A (LA)-activated autologous monocytes or supernatants recovered from LA-stimulated mononuclear cell cultures. In order to investigate the possible role of monocyte membrane-associated TNF-alpha, IL-1 alpha and IL-1 beta in the modulation of PMN activity, in a separate series of experiments LA-activated monocytes or LA-activated supernatants were pretreated with anti-recombinant human (Rhu) TNF alpha, anti-Rhu IL-1 alpha and anti-Rhu IL-1 beta monoclonal antibodies (MoAbs), respectively. Such an approach gave rise to an abrogation of monocyte-mediated triggering effect on PMN functional capacity. Taken together, these data suggest that activated monocytes can upregulate PMN phagocytosis by a cell-to-cell contact mechanism, likely related to membrane-associated CKs.
Jirillo
E
E
University of Bari Medical Faculty, Policlinico, Italy.
Decandia
P
P
Ribaud
M R
MR
Cannuscio
B
B
De Simone
C
C
Antonaci
S
S
D000911:Antibodies, Monoclonal; D002450:Cell Communication / Q000276:immunology; D002462:Cell Membrane / Q000276:immunology; D016207:Cytokines / Q000037:antagonists & inhibitors / Q000276:immunology*; D006801:Humans; D066298:In Vitro Techniques; D008050:Lipid A / Q000276:immunology; D009000:Monocytes / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology; D010587:Phagocytosis / Q000276:immunology*; D015854:Up-Regulation
D000911:Antibodies, Monoclonal; D016207:Cytokines; D008050:Lipid A