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A biologically active peptide mimetic of N-acetylgalactosamine/galactose.

Eggink LL, Hoober JK - BMC Res Notes (2009)

Bottom Line: The secretion of IL-21 was stimulated as strongly with the peptide as with interferon-gamma.The data indicate that the quadravalent peptide has biological activity with a degree of specificity.These effects occurred at concentrations in the nanomolar range, in contrast to free sugars that generally bind to proteins in the micro- to millimolar range.

View Article: PubMed Central - HTML - PubMed

Affiliation: Faculty of Biomedicine and Biotechnology, School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA. leggink@asu.edu

ABSTRACT

Background: Glycosylated proteins and lipids are important regulatory factors whose functions can be altered by addition or removal of sugars to the glycan structure. The glycans are recognized by sugar-binding lectins that serve as receptors on the surface of many cells and facilitate initiation of an intracellular signal that changes the properties of the cells. We identified a peptide that mimics the ligand of an N-acetylgalactosamine (GalNAc)-specific lectin and asked whether the peptide would express specific biological activity.

Findings: A 12-mer phage display library was screened with a GalNAc-specific lectin to identify an amino acid sequence that binds to the lectin. Phage particles that were eluted from the lectin with free GalNAc were considered to have been bound to a GalNAc-binding site. Peptides were synthesized with the selected sequence as a quadravalent structure to facilitate receptor crosslinking. Treatment of human peripheral blood mononuclear cells for 24 h with the peptide stimulated secretion of interleukin-8 (IL-8) but not of IL-1beta, IL-6, IL-10, or tumor necrosis factor-alpha (TNF-alpha). The secretion of IL-21 was stimulated as strongly with the peptide as with interferon-gamma.

Conclusion: The data indicate that the quadravalent peptide has biological activity with a degree of specificity. These effects occurred at concentrations in the nanomolar range, in contrast to free sugars that generally bind to proteins in the micro- to millimolar range.

No MeSH data available.


Related in: MedlinePlus

Stimulation of IL-21 release from PBMCs by treatment with L4. PBMCs were treated with 1 nM (400 U/ml) IFN-γ or 50 nM L4 for 16 h. The media were blotted onto membranes and stained with chicken anti-IL-21 antibodies and rabbit anti-chicken antibodies conjugated with peroxidase. The graph shows mean ± SEM values of four measurements.
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Figure 4: Stimulation of IL-21 release from PBMCs by treatment with L4. PBMCs were treated with 1 nM (400 U/ml) IFN-γ or 50 nM L4 for 16 h. The media were blotted onto membranes and stained with chicken anti-IL-21 antibodies and rabbit anti-chicken antibodies conjugated with peroxidase. The graph shows mean ± SEM values of four measurements.

Mentions: IL-21, a cytokine secreted from activated T cells, is of particular interest in regard to its pleiotropic immunomodulatory and anti-tumor activities [19,20]. A 16-h treatment of PBMCs with 50 nM L4 induced as strong a release of IL-21 as a highly effective concentration [1 nM (400 U/ml)] of IFN-γ, a known stimulant of IL-21 release [19] (Fig. 4). The low control value indicated that the peptide expressed an activity not provided by proteins and other factors from serum in the culture medium. IL-21 is most homologous to IL-15 and to a lesser extent IL-2. IL-21 has activity on all leukocyte subsets, including dendritic cells and monocytes [20]. IL-15 activates T cells and promotes long-term survival of memory T cells [21].


A biologically active peptide mimetic of N-acetylgalactosamine/galactose.

Eggink LL, Hoober JK - BMC Res Notes (2009)

Stimulation of IL-21 release from PBMCs by treatment with L4. PBMCs were treated with 1 nM (400 U/ml) IFN-γ or 50 nM L4 for 16 h. The media were blotted onto membranes and stained with chicken anti-IL-21 antibodies and rabbit anti-chicken antibodies conjugated with peroxidase. The graph shows mean ± SEM values of four measurements.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2657794&req=5

Figure 4: Stimulation of IL-21 release from PBMCs by treatment with L4. PBMCs were treated with 1 nM (400 U/ml) IFN-γ or 50 nM L4 for 16 h. The media were blotted onto membranes and stained with chicken anti-IL-21 antibodies and rabbit anti-chicken antibodies conjugated with peroxidase. The graph shows mean ± SEM values of four measurements.
Mentions: IL-21, a cytokine secreted from activated T cells, is of particular interest in regard to its pleiotropic immunomodulatory and anti-tumor activities [19,20]. A 16-h treatment of PBMCs with 50 nM L4 induced as strong a release of IL-21 as a highly effective concentration [1 nM (400 U/ml)] of IFN-γ, a known stimulant of IL-21 release [19] (Fig. 4). The low control value indicated that the peptide expressed an activity not provided by proteins and other factors from serum in the culture medium. IL-21 is most homologous to IL-15 and to a lesser extent IL-2. IL-21 has activity on all leukocyte subsets, including dendritic cells and monocytes [20]. IL-15 activates T cells and promotes long-term survival of memory T cells [21].

Bottom Line: The secretion of IL-21 was stimulated as strongly with the peptide as with interferon-gamma.The data indicate that the quadravalent peptide has biological activity with a degree of specificity.These effects occurred at concentrations in the nanomolar range, in contrast to free sugars that generally bind to proteins in the micro- to millimolar range.

View Article: PubMed Central - HTML - PubMed

Affiliation: Faculty of Biomedicine and Biotechnology, School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA. leggink@asu.edu

ABSTRACT

Background: Glycosylated proteins and lipids are important regulatory factors whose functions can be altered by addition or removal of sugars to the glycan structure. The glycans are recognized by sugar-binding lectins that serve as receptors on the surface of many cells and facilitate initiation of an intracellular signal that changes the properties of the cells. We identified a peptide that mimics the ligand of an N-acetylgalactosamine (GalNAc)-specific lectin and asked whether the peptide would express specific biological activity.

Findings: A 12-mer phage display library was screened with a GalNAc-specific lectin to identify an amino acid sequence that binds to the lectin. Phage particles that were eluted from the lectin with free GalNAc were considered to have been bound to a GalNAc-binding site. Peptides were synthesized with the selected sequence as a quadravalent structure to facilitate receptor crosslinking. Treatment of human peripheral blood mononuclear cells for 24 h with the peptide stimulated secretion of interleukin-8 (IL-8) but not of IL-1beta, IL-6, IL-10, or tumor necrosis factor-alpha (TNF-alpha). The secretion of IL-21 was stimulated as strongly with the peptide as with interferon-gamma.

Conclusion: The data indicate that the quadravalent peptide has biological activity with a degree of specificity. These effects occurred at concentrations in the nanomolar range, in contrast to free sugars that generally bind to proteins in the micro- to millimolar range.

No MeSH data available.


Related in: MedlinePlus