Lack of binding of peptides carrying the human platelet antigen 1 (HPA-1) dimorphism to purified HLA-DRw52a molecules.
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.
Braud
V
V
Centre Régional de Transfusion Sanguine, Nantes.
Valentin
N
N
Choppin
J
J
Cesbron
A
A
Bignon
J D
JD
Blanchard
D
D
Muller
J Y
JY
D000595:Amino Acid Sequence; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D016824:Antigens, Human Platelet / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018955:CD36 Antigens; D002850:Chromatography, Gel; D005260:Female; D006684:HLA-DR Antigens / Q000302:isolation & purification / Q000378:metabolism*; D059810:HLA-DR Serological Subtypes; D006801:Humans; D007114:Immunization; D007231:Infant, Newborn; D039661:Integrin beta3; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism*; D010641:Phenotype; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011485:Protein Binding; D013601:T-Lymphocytes / Q000276:immunology; D013921:Thrombocytopenia / Q000151:congenital / Q000453:epidemiology
D015703:Antigens, CD; D016824:Antigens, Human Platelet; D018955:CD36 Antigens; D006684:HLA-DR Antigens; D059810:HLA-DR Serological Subtypes; C051104:HLA-DR52 antigen; C061248:ITGB3 protein, human; D039661:Integrin beta3; D010446:Peptide Fragments; C083451:human platelet antigen 1b