Role of Tissue Factor in Adhesion of Mononuclear Phagocytes to and Trafficking Through Endothelium In Vitro

Abstract

An in vitro model consisting of endothelium grown on collagen was used to investigate how mononuclear phagocytes traverse endothelium in the basal-to-apical direction (reverse transmigration), a process that mimics their migration across vascular and/or lymphatic endothelium during atherosclerosis and resolution of inflammation, respectively. Monoclonal antibody (MoAb) VIC7 against tissue factor (TF) inhibited reverse transmigration by 77%. Recombinant tissue factor fragments containing at least six amino acids C-terminal to residue 202 also strongly inhibited reverse transmigration. TF was absent on resting monocytes but was induced on these cells after initial apical-to-basal transendothelial migration. Two additional observations suggest that TF is involved in adhesion between mononuclear phagocytes and endothelium: (1) when monocytes were incubated with lipopolysaccharide (LPS) to stimulate expression of TF before they were added to endothelium, VIC7 or soluble TF modestly inhibited their adhesion to the apical endothelial surface, each by about 35%; and (2) endothelial cells specifically bound to surfaces coated with TF fragments containing amino acids 202-219. This binding was blocked by anti-TF MoAb, suggesting that endothelial cells bear a receptor for TF. These data suggest that mononuclear phagocytes use TF, perhaps as an adhesive protein, to exit sites of inflammation.

Effects of HIV-1 infection in vitro on transendothelial migration by monocytes and monocyte-derived macrophages

“…Westhorpe, S. M. Crowe, and A. Jaworowski, unpublished data). As these receptors have been implicated in monocyte/ macrophage migration [7,12,32,36], this suggests that defective migration does not occur at the level of substrate binding. Finally, there was no evidence of multinuclear giant cell formation by HIV-infected MDM in the subendothelial collagen within the 48-h culture period required for reverse TEM (data not shown).…”

“…1A, and data not shown). Purified monocytes also expressed chemokine receptors that support forward TEM (CCR2 and CX 3 CR1) and reverse TEM (CCR8) but did not express p-gp, the lipid efflux protein implicated in reverse TEM [36]. Purified monocytes cultured for 5 days in suspension (MDM) had similar levels of expression of CD49d, CD49e, CD18, PECAM-1, CCR2, and CCR8 as purified monocytes (Fig.…”

Intravascular tissue factor initiates coagulation via circulating microvesicles and platelets

“…The monoclonal anti-human TF antibodies directed against extracellular epitopes of the human TF were clones VIC7, VD8, and IIID8 (16). Fluorescein-isothiocyanate (FITC)-labeled monoclonal anti-human TF antibody, phycoerythrin (PE)-labeled monoclonal anti-CD14, and anti-CD15 antibodies were obtained from Biotrend.…”

Migration of Leukocytes across Endothelial Junctions: Some Concepts and Controversies

“…However, none of the molecules involved in adhesion to or transmigration across endothelium in the apical-to-basal direction appear to be involved in this reverse transmigration. Neither blocking monoclonal nor polyclonal antibodies against PECAM-1, VCAM-1, or Lselectin block reverse transmigration (60,61,63). Antibodies against CD18 were found in one system to slow it for the first few hours, but by 6 hours equivalent levels of reverse-migrated cells were seen (61).…”

“…Such sightings have been rare, and whether this represents a major trafficking pathway of leukocytes remains controversial. Under the conditions used by Randolph and colleagues (60,63), the reverse transmigration system has been shown to be a model of the process of migration into lymphatic vessels. However, under the appropriate experimental conditions, this may serve as a model of reverse transmigration across vascular endothelium as well.…”