Monocyte adherence to fibronectin: role of CD11/CD18 integrins and relationship to other monocyte functions

Abstract

Adherence of monocytes to extracellular matrix components is critical for their accumulation at sites of infection. To gain insight into the factors that regulate monocyte recruitment, we have studied monocyte adherence with regard to the regulatory effects of bacterial lipopolysaccharide (LPS) and the mechanisms involved; moreover, we have contrasted the phenotypes of adherent and nonadherent cells. Our results show that only a minor subpopulation of monocytes (20-25%) adhere spontaneously to fibronectin and that LPS stimulated a threefold increase in the proportion of adherent cells. Basal adherence and LPS-stimulated adherence of monocytes to fibronectin were substantially mediated by CD11/CD18 integrins. Further studies revealed that spontaneously adherent monocytes were 14-fold more actively phagocytic, released 1.6-fold more superoxide anion, and contained 20-fold more peroxidase activity than nonadherent cells, whereas LPS-adherent cells had an intermediate phenotype. These results indicate that LPS may enhance the accumulation of monocytes with an antimicrobial phenotype and thereby promote resolution of tissue infection.

Cell Adhesion Molecules CD11a and CD18 in Blood Monocytes in Old Age and the Consequences for Immunological Dysfunction

“…The densities of CD54 antigen on lympho cytes and monocytes from the two groups studied were not different (data not shown), while CD44 antigen density on monocytes from old subjects was higher than that of young controls (225 ± 24 in comparison with 168 ± 14 in young subjects; p<0.04). [18], these mono cytes might represent one of the most impor tant populations involved in the in vitro pro liferative response as well as in vivo at the sites of infection and inflammation. Dougher ty and Hogg [19] demonstrated that CD1 la/ CD 18 (LFA-1) plays an important role in the generation of an immune response against the antigen.…”

Cross-talk between human monocytes and cancer cells during reactive oxygen intermediates generation: The essential role of hyaluronan

“…26 The candidate for a ligand for both CD18 and CD29 may be fibronectin, which, although not expressed on the plasma membrane, is produced, secreted by and closely associated with tumor cells. 27,28 However, although HPC-4 cells express CD29, pretreatment with fibronectin did not alter their stimulatory capacity. On the other hand, the role of tumor cell-derived fibronectin is further exemplified by our recent findings that monocytes after 4 -6 hr culture with cancer cells show decreased expression of CD29 (unpublished observations).…”

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

“…The intracellular location of this pool is not clearly defined but it has been suggested that monocytes, like neutrophils, have easily mobilizable secretory vesicles [18], which contain CD11b/CD18. Previous studies have revealed that monocyte adherence to extracellular matrix is substantially mediated by CD11b/CD18 [19].…”