title: Effects of transmembrane region variability on cell surface expression and allorecognition of HLA-DP3.
abstract: The functional relevance of polymorphisms outside the peptide binding groove of HLA molecules is poorly understood. Here we have addressed this issue by studying HLA-DP3, a common antigen relevant for functional matching algorithms of unrelated hematopoietic stem cell transplantation (HSCT) encoded by two transmembrane (TM) region variants, DPB1(*)03:01 and DPB1(*)104:01. The two HLA-DP3 variants were found at a overall allelic frequency of 10.4% in 201 volunteer stem cell donors, at a ratio of 4.2:1. No significant differences were observed in cell surface expression levels of the two variants on B lymphoblastoid cell lines (BLCL), primary B cells or monocytes. Three different alloreactive T cell lines or clones showed similar levels of activation marker CD107a and/or CD137 upregulation in response to HLA-DP3 encoded by DPB1(*)03:01 and DPB1(*)104:01, either endogenously on BLCL or after lentiveral-vector mediated transfer into the same cellular background. These data provide, for the first time, direct evidence for a limited functional role of a TM region polymorphism on expression and allorecognition of HLA-DP3 and are compatible with the notion that the two variants can be considered as a single functional entity for unrelated stem cell donor selection.
authors.affiliation: Unit of Molecular and Functional Immunogenetics, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Crivello
authors.forename: Nina
authors.initials: N
authors.lastname: Lauterbach
authors.forename: Laura
authors.initials: L
authors.lastname: Zito
authors.forename: Federico
authors.initials: F
authors.lastname: Sizzano
authors.forename: Cristina
authors.initials: C
authors.lastname: Toffalori
authors.forename: Jessica
authors.initials: J
authors.lastname: Marcon
authors.forename: Laura
authors.initials: L
authors.lastname: Curci
authors.forename: Arend
authors.initials: A
authors.lastname: Mulder
authors.forename: Lotte
authors.initials: L
authors.lastname: Wieten
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Zino
authors.forename: Christien E M
authors.initials: CE
authors.lastname: Voorter
authors.forename: Marcel G J
authors.initials: MG
authors.lastname: Tilanus
authors.forename: Katharina
authors.initials: K
authors.lastname: Fleischhauer
mesh_terms: D000483:Alleles; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D015870:Gene Expression; D005787:Gene Frequency; D014644:Genetic Variation; D059868:HLA-DP beta-Chains / Q000235:genetics* / Q000378:metabolism*; D006648:Histocompatibility / Q000235:genetics / Q000276:immunology; D006650:Histocompatibility Testing; D006801:Humans; D016130:Immunophenotyping; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D061349:Unrelated Donors
chemical_list: D059868:HLA-DP beta-Chains; C055961:HLA-DPw3 antigen
keywords: BLCL; Epstein–Barr Virus transformed B lymphoblastoid cell lines; GvHD; HSCT; LV; MESF; MFI; MLR; PBMC; PCR-SSP; PCR-sequence specific priming; R; S; T cell epitope; TCE; TM; VUD; gamma interferon; graft versus host disease; hPGK; hematopoietic stem cell transplantation; human phosphoglycerate kinase; lentiviral expression vector; median fluorescence intensity; mixed lymphocyte reaction; molecules of equivalent soluble fluorochrome; peripheral blood mononuclear cells; responder donor; stimulator donor; transmembrane; truncated form of the human low affinity nerve growth factor receptor; volunteer unrelated donors; ΔLNGFR; γ-IFN