Abstract
The strong association between anti-HPA-1a alloimmunization and DR3, DRw52a phenotype in HPA-1b homozygous women suggests that these class II molecules play a crucial role in the immune response against HPA-1a. The diallelic system HPA-1 results in a single amino acid polymorphism at the residue 33 of the glycoprotein IIIa. So, we tested the binding of peptides from the 25-42 region of the GPIIIa to purified HLA-DR3 and -DRw52a molecules, using a solid phase assay and a liquid phase peptide binding assay. No binding was demonstrated, indicating that either the crucial region for binding to class II molecules is not the 25-42 region, or that other events only occurring "in vivo" are required for binding. These results may also suggest an indirect role of the residue 33 for T-cell stimulation.
MeSH terms
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Amino Acid Sequence
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Antigens, CD / genetics
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Antigens, CD / immunology
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Antigens, CD / metabolism*
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Antigens, Human Platelet / genetics
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Antigens, Human Platelet / immunology
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Antigens, Human Platelet / metabolism*
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CD36 Antigens
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Chromatography, Gel
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Female
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HLA-DR Antigens / isolation & purification
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HLA-DR Antigens / metabolism*
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HLA-DR Serological Subtypes
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Humans
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Immunization
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Infant, Newborn
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Integrin beta3
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Molecular Sequence Data
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Peptide Fragments / chemical synthesis
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Peptide Fragments / metabolism*
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Phenotype
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Polymorphism, Genetic
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Pregnancy
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Protein Binding
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T-Lymphocytes / immunology
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Thrombocytopenia / congenital
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Thrombocytopenia / epidemiology
Substances
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Antigens, CD
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Antigens, Human Platelet
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CD36 Antigens
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HLA-DR Antigens
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HLA-DR Serological Subtypes
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HLA-DR52 antigen
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ITGB3 protein, human
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Integrin beta3
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Peptide Fragments
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human platelet antigen 1b