Divalent cation substitution reveals CD18- and very late antigen-dependent pathways that mediate human neutrophil adherence to fibronectin.
We investigated the mechanisms by which Mn2+ alters human neutrophil (PMN) adherence to various connective tissue proteins. Substitution of Mn2+ for Ca2+ and Mg2+ significantly increased adhesion of human PMN to plastic well coated with fibronectin, fibrinogen, and laminin but not gelatin. Anti-CD18 mAb almost completely blocked adherence to laminin, partly blocked adherence to fibrinogen, but did not inhibit adhesion to fibronectin at all. In contrast, anti-very late antigen (VLA)-5 mAb antibodies significantly reduced Mn(2+)-mediated PMN adherence to fibronectin, but not to laminin or fibrinogen, demonstrating that VLA-5-mediated PMN adherence to fibronectin, but not to fibrinogen or laminin. This was supported by experiments in which synthetic GRGDSP peptide significantly inhibited Mn(2+)-mediated adherence to fibronectin, but not to laminin or fibrinogen. Activation of PMN with phorbol ester or C5a stimulated VLA-5-mediated adhesion to fibronectin, but the contribution of VLA-5 to the forces mediating adherence could only be detected when CD18 function was either blocked with mAb, or when CD18 was congenitally absent. VLA-5 mediated adhesion was also more transient than CD18-dependent adhesion. These data further confirm the presence of PMN VLA integrins and demonstrate that PMN VLA-5 contributes to stimulated PMN adherence to fibronectin.
Department of Pediatrics and Pathology, University of Utah School of Medicine, Salt Lake City 84132.
J F
JF
Bohnsack
X N
XN
Zhou
D015703:Antigens, CD / Q000378:metabolism*; D018821:CD18 Antigens; D002118:Calcium / Q000378:metabolism; D002413:Cations, Divalent; D002448:Cell Adhesion; D005340:Fibrinogen / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism*; D005434:Flow Cytometry; D005780:Gelatin / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007797:Laminin / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D008345:Manganese / Q000378:metabolism*; D009504:Neutrophils / Q000166:cytology*; D016029:Receptors, Very Late Antigen / Q000378:metabolism*; D013997:Time Factors
D015703:Antigens, CD; D018821:CD18 Antigens; D002413:Cations, Divalent; D005353:Fibronectins; D007797:Laminin; D016029:Receptors, Very Late Antigen; D008345:Manganese; D005780:Gelatin; D005340:Fibrinogen; D008274:Magnesium; D002118:Calcium