title: Structural identity between HLA-A2 antigens differentially recognized by alloreactive cytotoxic T lymphocytes.
abstract: Alloreactive CTL raised against HLA-A2 Ag often display heterogeneous recognition of HLA-A2+ target cells. This heterogeneity has been found to reflect structural polymorphism among the corresponding target Ag, thus defining HLA-A2 subtypes. A previous study (van der Poel et al. 1986. Human Immunol. 16:247) established the existence of a new HLA-A2.4 variant, A2-SCHU, that was distinguished from A*0206 (A2.4a) by HLA-A2-specific alloreactive CTL. The same CTL subdivided HLA-A2.1 Ag into two subgroups. In the present study, the molecular basis of this heterogeneity has been examined by double-label comparative peptide mapping analysis of differentially recognized A2.1 and A2.4 Ag. In addition, we have determined the complete sequence of polymerase chain reaction-amplified full length cDNA from A2-SCHU. The results show that: 1) A2-SCHU is indistinguishable from A*0206 by peptide mapping; 2) the cDNA sequence of A2-SCHU is identical to that of A*0206; and 3) two differentially recognized A2.1 Ag are both indistinguishable from A*0201 by comparative peptide mapping. These results indicate that differential recognition by alloreactive CTL can occur among structurally identical class I HLA Ag and suggest that allorecognition by such CTL may involve corecognition of endogenous peptides, presumably derived from polymorphic proteins.
authors.affiliation: Department of Immunology, Fundación Jiménez Díaz, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: A R
authors.initials: AR
authors.lastname: Castaño
authors.forename: P
authors.initials: P
authors.lastname: Lauzurica
authors.forename: N
authors.initials: N
authors.lastname: Domenech
authors.forename: J A
authors.initials: JA
authors.lastname: López de Castro
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015789:HLA-A2 Antigen / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D016133:Polymerase Chain Reaction; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D015789:HLA-A2 Antigen