Induction of cell‐associated interleukin 1 through stimulation of the adhesion‐promoting proteins LFA‐1 (CD11a/CD18) and CR3 (CD11b/CD18) of human monocytes

Abstract

Serum-free culture of human monocytes in the presence of monoclonal antibodies to the LFA-1 alpha chain (CD11a), CR3 alpha chain (CD11b) or beta chain (CD18) bound to Sepharose induced the dose-dependent production of cell-associated interleukin (IL) 1 activity and of IL 1 alpha and IL 1 beta antigens, but no release of extracellular IL 1 activity or antigen in the culture medium. Triggering of IL 1 production was also observed with insolubilized anti-CD11/CD18 F(ab')2 antibodies. Two cross-linked antibodies recognizing distinct epitopes on the CD11b molecule induced cell-associated IL 1. Soluble antibodies did not induce IL 1 production. The kinetics of induction of IL 1 by stimulation of adhesion-promoting proteins differed from those of IL 1 induction by adhesion to plastic. The lack of induction of IL 1 release by stimulation of the CD11/CD18 molecules resembled the intracellular accumulation of IL 1 induced by lipid A. Induction of IL 1 by adhesive processes may be a mechanism by which T cells trigger IL 1 production by monocytes during antigen presentation.

Systemic human Netrin-1 gene delivery by adeno-associated virus type 8 alters leukocyte accumulation and atherogenesis in vivo

“…ND control mice had very low CD68 levels. Integrin, alpha M (ITGAM) is another MF marker 20 and, again, ITGAM staining (Figure 7c) was much lower in hNetrin-1-treated animals than in Neo-treated animals, similar to CD68.…”

Effects of Escherichia coli hemolysin on human monocytes. Cytocidal action and stimulation of interleukin 1 release.

“…Secretion of the active 17K IL-la and IL-1(3 molecules probably occurs via a novel mechanism that is currently under investigation (34). Production ofboth IL-1 a and IL-13 31K precursors is apparently triggered when cells become adherent and during short-term culture, whereby the cytokines remain predominantly cell-associated (35)(36)(37)(38). Cellbound IL-I has previously been quantified mainly with the use of bioassays.…”

Human blood monocytes, but not alveolar macrophages, reveal increased CD11b/CD18 expression and adhesion properties upon receptor-dependent activation

“…Adherence is an important immunological step that is not only essential for the migration process but also serves as an important signal for a variety of different functions [8][9][10][11][12][13][14][15]. Adherence events can also prime the cells for augmented activity in the presence of an additional environmental stimuli [28].…”

“…For this purpose, monocytes are equipped with specific cell surface receptors. The receptorligand interaction has far-reaching effects on monocyte differentiation [7], and functions such as phagocytosis [8,9], cytotoxicity [10], arachidonic acid metabolism [11] and gene expression of inflammatory cytokines [12][13][14][15]. Based on these observations, it has been suggested that adherence is an important primary and amplifying signal for the differentiation and activation of monocytes/ macrophages.…”