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

J Clin Invest. 1996 Oct 15;98(8):1802-8. doi: 10.1172/JCI118980.

Abstract

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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antigens, Human Platelet / immunology*
  • Cells, Cultured
  • DNA, Complementary / analysis
  • Female
  • Humans
  • Infant, Newborn
  • Polymerase Chain Reaction
  • Pregnancy
  • Receptors, Antigen, T-Cell, alpha-beta / genetics*
  • T-Lymphocytes / immunology*
  • Thrombocytopenia / immunology*

Substances

  • Antigens, Human Platelet
  • DNA, Complementary
  • ITGB3 protein, human
  • Receptors, Antigen, T-Cell, alpha-beta