title: T cell immunobiology of alloimmune thrombocytopenias.
abstract: Allorecognition and generation of alloantisera depend on T cell help. Here we summarize our recent work on identifying the T cells that recognize a specific platelet alloantigen generated by a Pro to Leu polymorphism in beta-chain of the platelet integrin alphaIIb beta3. The ability to generate alloantibodies is restricted by HLA-DRB3*0101. By measuring peptide binding to HLA-DRB3*0101, we have shown that the polymorphism controls the generation of the T cell epitope. This is not a result of the polymorphism changing a T cell contact residue, but rather by its generating a peptide anchor. The result is a directional antibody response in which only the beta-chain that is antigenic is the one that produces a peptide that binds to the HLA-DR. This mechanism of generating alloantibodies may be a paradigm for a whole class of responses.
authors.affiliation: Blood Research Institute, Blood Center of Southeastern Wisconsin, Milwaukee 53201-2178, USA.
authors.forename: J
authors.initials: J
authors.lastname: Gorski
authors.forename: M
authors.initials: M
authors.lastname: Yassai
authors.forename: S
authors.initials: S
authors.lastname: Wu
authors.forename: K
authors.initials: K
authors.lastname: Maślanka
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000276:immunology; D006801:Humans; D007519:Isoantigens / Q000276:immunology*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000235:genetics / Q000276:immunology*; D011110:Polymorphism, Genetic; D013601:T-Lymphocytes / Q000276:immunology*; D013921:Thrombocytopenia / Q000097:blood / Q000276:immunology*
chemical_list: D007519:Isoantigens; D019039:Platelet Glycoprotein GPIIb-IIIa Complex