Molecular identification of T cells that respond in a primary bulk culture to a peptide derived from a platelet glycoprotein implicated in neonatal alloimmune thrombocytopenia.
Neonatal alloimmune thrombocytopenia induced by the human platelet alloantigen 1a (HPA1a) is characterized by generation of alloantibodies by a mother who is homozygous for the HPA1b alloantigen and almost always HLA-DRB3*0101. The disease is viewed as B cell mediated but the linkage with HLA is indicative of a role for T cells. The HPA1a and HPA1b allotypes are defined, respectively, by Leu and Pro at amino acid 33 of the beta-chain of the platelet integrin GPIIbIIIa (alpha(IIb)beta3). Under the assumption that the same polymorphism may control both the B cell epitope and constitute the MHC-bound peptide, we restimulated PBMC from a woman with an affected child with a synthetic peptide from this polymorphic region. Molecular analysis of the responding T cell repertoire identified two T cells which predominated in cultures stimulated with the alloantigen peptide and which were absent in cultures with the autoantigen peptide. In spite of the use of different V families, sequence of the CDR3 region of the T cell receptor (TCR) beta-chain revealed the presence of a shared motif, L-P-S/T. Oligonucleotide probes specific for the CDR3 sequence indicated that these T cells were present in the PBMC at the highest levels immediately after delivery of the affected infant and their frequency dropped at later times.
Maslanka
K
K
Immunogenetics Research Section, Blood Research Institute, The Blood Center of Southeastern Wisconsin, Milwaukee 53201-2178, USA.
Yassai
M
M
Gorski
J
J
D016824:Antigens, Human Platelet / Q000276:immunology*; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000032:analysis; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D039661:Integrin beta3; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D013601:T-Lymphocytes / Q000276:immunology*; D013921:Thrombocytopenia / Q000276:immunology*
D016824:Antigens, Human Platelet; D018076:DNA, Complementary; C061248:ITGB3 protein, human; D039661:Integrin beta3; D016693:Receptors, Antigen, T-Cell, alpha-beta