Binding of human serum amyloid P componentto L-selectin.
Serum concentrations of soluble L-selectin by far exceed those of other soluble adhesion molecules, and serum soluble L-selectin concentrations are remarkably stable upon prolonged storage. We present evidence for Ca(2+)-dependent binding interactions between human serum amyloid P (SAP), a proteolysis-resistant pentraxin glycoprotein, and L-selectin, as shown by surface plasmon resonance measurements, protein band shift assays in a native PAGE system, and after SDS-PAGE and membrane transfer. Monoclonal antibodies to L-selectin strongly reduced binding of biotinylated SAP to L-selectin-IgG chimeras immobilized on microtiter plates. As binding was reduced by prior glycopeptidase F treatment of L-selectin but not of SAP, it appears to be based on SAP lectin domain interactions with N-linked L-selectin carbohydrates. In freshly prepared human lymphocytes, SAP incubation induced expression of a beta2 integrin neoepitope associated with high-affinity binding. This was partially blocked by pre-incubation with Fab fragments of two anti-L-selectin antibodies. In flow chamber experiments, SAP inhibited the adherence of human neutrophils to activated endothelium under shear stress. Thus, SAP binds to human L-selectin and affects L-selectin-dependent leukocyte-endothelial interactions.
Stibenz
Dietger
D
Department of Neonatology, Charité Virchow Hospital, Humboldt University, Berlin, Germany.
Gräfe
Michael
M
Debus
Nils
N
Hasbach
Michael
M
Bahr
Inke
I
Graf
Kristof
K
Fleck
Eckart
E
Thanabalasingam
Usan
U
Bührer
Christoph
C
D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000276:immunology; D002118:Calcium / Q000737:chemistry* / Q000378:metabolism; D002241:Carbohydrates / Q000737:chemistry / Q000276:immunology; D002448:Cell Adhesion / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000276:immunology; D006801:Humans; D019041:L-Selectin / Q000737:chemistry* / Q000276:immunology; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology; D009504:Neutrophils / Q000276:immunology; D011485:Protein Binding / Q000276:immunology; D000683:Serum Amyloid P-Component / Q000737:chemistry* / Q000276:immunology / Q000494:pharmacology; D013314:Stress, Mechanical; D020349:Surface Plasmon Resonance / Q000379:methods; D001613:beta 2-Microglobulin / Q000276:immunology
D000911:Antibodies, Monoclonal; D002241:Carbohydrates; D000683:Serum Amyloid P-Component; D001613:beta 2-Microglobulin; D019041:L-Selectin; D002118:Calcium