An immunosuppressive and anti-inflammatory HLA class I-derived peptide binds vascular cell adhesion molecule-1.
BACKGROUND
A synthetic peptide corresponding to residues 75-84 of HLA-B2702 modulates immune responses in rodents and humans both in vitro and in vivo.


METHODS
We used a yeast two-hybrid screening, an in vitro biochemical method, and an in vivo animal model.


RESULTS
Two cellular receptors for this novel immunomodulatory peptide were identified using a yeast two-hybrid screen: immunoglobulin binding protein (BiP), a member of the heat shock protein 70 family, and vascular cell adhesion molecule (VCAM)-1. Identification of BiP as a ligand for this peptide confirms earlier biochemical findings, while the interaction with VCAM-1 suggests an alternative mechanism of action. Binding to the B2702 peptide but not to closely related variants was confirmed by ligand Western blot analysis and correlated with immunomodulatory activity of each peptide. In mice, an ovalbumin-induced allergic pulmonary response was blocked by in vivo administration of either the B2702 peptide or anti-VLA-4 antibody.


CONCLUSIONS
We propose that the immunomodulatory effect of the B2702 peptide is caused, in part, by binding to VCAM-1, which then prevents the normal interaction of VCAM-1 with VLA-4.
Ling
X
X
Division of Immunology and Transplantation Biology, Stanford University, California 94305, USA.
Tamaki
T
T
Xiao
Y
Y
Kamangar
S
S
Clayberger
C
C
Lewis
D B
DB
Krensky
A M
AM
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000276:immunology; D000091342:Endoplasmic Reticulum Chaperone BiP; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000276:immunology; D006360:Heat-Shock Proteins; D015395:Histocompatibility Antigens Class I / Q000737:chemistry / Q000276:immunology*; D006967:Hypersensitivity / Q000276:immunology; D008171:Lung Diseases / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D018832:Molecular Chaperones / Q000737:chemistry / Q000276:immunology; D008969:Molecular Sequence Data; D010047:Ovalbumin / Q000276:immunology; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology* / Q000494:pharmacology; D012441:Saccharomyces cerevisiae; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D019010:Vascular Cell Adhesion Molecule-1 / Q000276:immunology*
D002352:Carrier Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D015395:Histocompatibility Antigens Class I; D018832:Molecular Chaperones; D010446:Peptide Fragments; D019010:Vascular Cell Adhesion Molecule-1; C118185:decapeptide B 2702; D010047:Ovalbumin