Increased plasma GlyCAM-1, a mouse L-selectin ligand, in response to an inflammatory stimulus.
GlyCAM-1 (glycosylation-dependent cell adhesion molecule-1) is one of the sialomucin-like ligands for L-selectin, which is a member of the selectin family and mediates initial adhesion of leukocytes to specialized high endothelial venules in lymph nodes and venules at sites of inflammation. GlyCAM-1, lacking a transmembrane domain, is supposed to be secreted into the blood. To understand the functional role of secreted GlyCAM-1, we performed sandwich enzyme-linked immunosorbent assay to measure GlyCAM-1 plasma levels after inflammatory stimulus. BALB/c mice were injected with complete Freund's adjuvant (CFA) in the hind footpads; serum levels of GlyCAM-1 and L-selectin bound to GlyCAM-1 and several inflammatory cytokines, including interleukin-6 (IL-6), were measured at various intervals. IL-6 showed a significant increase 3 h after CFA stimulation. GlyCAM-1 was increased at 3 h, reached peak levels at 12 h, and gradually decreased thereafter. Levels of L-selectin bound to the plasma GlyCAM-1 changed over a similar time course, reached peak at 12 h after, and then began to decrease. The binding of L-selectin to plasma GlyCAM-1 was completely eliminated with the presence of ethyleneglycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid, showing the calcium dependency of this binding. These findings show that GlyCAM-1 release is enhanced by inflammatory stimulation and also suggest that released plasma GlyCAM-1 may trap, at least in part, soluble L-selectin shed from stimulated leukocytes to neutralize each other.
Suguri
T
T
First Department of Surgery, Okayama University Medical School, Japan.
Kikuta
A
A
Iwagaki
H
H
Yoshino
T
T
Tanaka
N
N
Orita
K
K
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D016207:Cytokines / Q000097:blood; D004533:Egtazic Acid / Q000494:pharmacology; D005620:Freund's Adjuvant / Q000633:toxicity; D007249:Inflammation / Q000097:blood* / Q000139:chemically induced; D015850:Interleukin-6 / Q000097:blood; D019041:L-Selectin / Q000378:metabolism*; D008024:Ligands; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009077:Mucins / Q000097:blood*; D011485:Protein Binding / Q000187:drug effects
D002614:Chelating Agents; D016207:Cytokines; D015850:Interleukin-6; D008024:Ligands; D009077:Mucins; D019041:L-Selectin; C075185:sulfated glycoprotein p50; D004533:Egtazic Acid; D005620:Freund's Adjuvant; D002118:Calcium