Anti-L-selectin oligonucleotide ligands recognize CD62L-positive leukocytes: binding affinity and specificity of univalent and bivalent ligands.
Oligonucleotide aptamers generated against purified LS-Rg, a human L-selectin/IgG fusion protein, bound human CD62L-positive leukocytes. FACS analysis of lymphocytes or neutrophils stained with fluorescently labeled aptamers indicated specificity and sensitivity for cellular L-selectin similar to that observed with anti-L-selectin antibody. Univalent aptamers were compared to bivalent aptamers as well as to the anti-adhesion, anti-L-selectin antibody DREG56. Equilibrium and kinetic binding experiments were performed to examine the affinity and kinetic binding parameters of L-selectin aptamers to evaluate their binding to CD62L-positive leukocytes and to test their potential as L-selectin antagonists. Binding experiments indicated that bivalent aptamers approached the affinity and the dissociation rate of bivalent antibody, and preferentially recognized cellular compared to soluble L-selectin, a potentially useful distinction in vivo. Anti-L-selectin aptamers also inhibited L-selectin dependent self-adhesion of neutrophils suggesting that in vitro univalent and bivalent aptamers provided anti-adhesion activity similar to that observed with blocking antibody and indicated a direct blocking mechanism of action during inhibition of L-selectin-dependent trafficking of lymphocytes observed in vivo.
Ringquist
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NeXstar Pharmaceuticals, Inc., Boulder, Colorado 80301, USA.
Parma
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D
D001483:Base Sequence; D002448:Cell Adhesion; D006801:Humans; D007700:Kinetics; D019041:L-Selectin / Q000032:analysis* / Q000276:immunology; D007962:Leukocytes / Q000276:immunology*; D008024:Ligands; D008214:Lymphocytes / Q000276:immunology; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism; D009841:Oligonucleotides / Q000276:immunology*; D012995:Solubility; D013194:Staining and Labeling
D008024:Ligands; D009841:Oligonucleotides; D019041:L-Selectin