T-cell responses associated with neonatal alloimmune thrombocytopenia: isolation of HPA-1a-specific, HLA-DRB3*0101-restricted CD4+ T cells.
T-cell responses have been implicated in the development of HPA-1a-induced neonatal alloimmune thrombocytopenia (NAIT). However, HPA-1a-specific T cells have neither been isolated nor characterized. Here, we aimed to determine whether HPA-1a-specific T cells could be isolated from HPA-1a-immunized women. In the present study, peripheral blood mononuclear cells (PBMCs) from an HPA-1a-alloimmunized woman were cultured for weeks in the presence of HPA-1a peptide, labeled with CFSE, and assayed for antigen-specific proliferation. Individual proliferating cells were isolated by fluorescence-activated cell sorting and expanded in culture. Antigen specificity and HLA restriction were determined by cytokine secretion (enzyme-linked immunospot [ELISPOT]) and proliferation assays. Several CD3(+)CD4(+) T-cell clones were isolated that proliferated and secreted cytokines in response to HPA-1a peptide. Two of these clones have been established in long-term culture in our laboratory. Both of these recognize synthetic as well as naturally processed HPA-1a antigen, and the recognition is restricted by the MHC molecule HLA-DRB3*0101 that is strongly associated with NAIT. These HPA-1a-specific T-cell clones represent unambiguous evidence for the association of T-cell responses with NAIT, and they will serve as unique tools to elucidate the cellular immune response that may result in NAIT.
Ahlen
Maria Therese
MT
Department of Immunology and Transfusion Medicine, University Hospital of North Norway, Tromsø.
Husebekk
Anne
A
Killie
Mette Kjaer
MK
Skogen
Bjørn
B
Stuge
Tor B
TB
D000328:Adult; D016824:Antigens, Human Platelet / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D016207:Cytokines / Q000276:immunology; D005260:Female; D006684:HLA-DR Antigens / Q000276:immunology*; D059826:HLA-DRB3 Chains; D006801:Humans; D007231:Infant, Newborn; D010455:Peptides / Q000276:immunology*; D054098:Thrombocytopenia, Neonatal Alloimmune / Q000276:immunology*
D016824:Antigens, Human Platelet; D016207:Cytokines; D006684:HLA-DR Antigens; D059826:HLA-DRB3 Chains; D010455:Peptides