Role of lymphocyte function-associated antigen-1 on the interplay between lipid A-activated monocytes and polymorphonuclear cells.
Previous findings provided evidence that bacterial lipopolysaccharide (LPS)-activated human monocytes are able to upregulate autologous polymorphonuclear (PMN) phagocytic ability via cell-to-cell contact mechanisms mediated by membrane (m)-associated cytokines (CKs), such as tumour necrosis factor (TNF)-alpha, interleukin (IL)-1 alpha, IL-1 beta, IL-6 and IL-8. Consequently, the role of the lymphocyte function-associated antigen (LFA)-1 molecule on the monocyte (Mo)-PMN interplay was evaluated. In the first step, lipid A (LA)-stimulated Mo were pretreated with anti-recombinant human (Rhu) LFA-1 alpha monoclonal antibody (MoAb), and the enhanced phagocytic activity of PMN was abrogated. Pretreatment of unstimulated Mo with the same MoAb led to a reduction of PMN phagocytosis. In the second step, the role of m-LFA-1 on PMN was investigated with regard to Mo modulation. Anti-Rhu LFA-1 alpha MoAb was supplemented to LA-activated and unstimulated PMN, respectively, before coculturing with autologous LA-activated Mo. The addition of anti-Rhu LFA-1 alpha MoAb gave rise to a significant decrease in PMN phagocytosis regardless of PMN activation. These data suggest that, besides m-CKs, LFA-1 present on Mo and PMN might be involved in the mutual interplay between PMN and Mo.
D000911:Antibodies, Monoclonal; D002450:Cell Communication; D006801:Humans; D008050:Lipid A / Q000378:metabolism; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology*; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology*; D010587:Phagocytosis / Q000502:physiology
D000911:Antibodies, Monoclonal; D008050:Lipid A; D016169:Lymphocyte Function-Associated Antigen-1