title: Human leukocyte antigen epitope antigenicity and immunogenicity.
abstract: OBJECTIVE
  Human leukocyte antigen (HLA) antibodies are now recognized as being specific for epitopes which can be defined structurally with amino acid differences between HLA alleles. This article addresses two general perspectives of HLA epitopes namely antigenicity, that is their reactivity with antibody and immunogenicity, that is their ability of eliciting an antibody response.
  
  
  RESULTS
  Single-antigen bead assays have shown that HLA antibodies recognize epitopes that are equivalent to eplets or corresponding to eplets paired with other residue configurations. There is now a website-based Registry of Antibody-Defined HLA Epitopes (http://www.epregistry.com.br). Residue differences within eplet-defined structural epitopes may also explain technique-dependent variations in antibody reactivity determined in Ig-binding, C1q-binding and lymphocytotoxicity assays.HLA antibody responses correlate with the numbers of eplets on mismatched HLA antigens, and the recently proposed nonself-self paradigm of epitope immunogenicity may explain the production of epitope-specific antibodies.
  
  
  CONCLUSIONS
  These findings support the usefulness of HLA matching at the epitope level, including the identification of acceptable mismatches for sensitized patients and permissible mismatching for nonsensitized patients aimed to reduce HLA antibody responses.
authors.affiliation: Division of Transplant Pathology, Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: René J
authors.initials: RJ
authors.lastname: Duquesnoy
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000917:Antibody Formation / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D006680:HLA Antigens / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans
chemical_list: D000906:Antibodies; D000939:Epitopes; D006680:HLA Antigens