title: Molecular cloning and DNA sequence analysis of genes encoding cytotoxic T lymphocyte-defined HLA-A3 subtypes: the E1 subtype.
abstract: Influenza-specific cytotoxic T cells restricted by HLA-A3 and allogeneic CTL specific for HLA-A3 recognize differences between serologically indistinguishable HLA-A3 antigens. Previous biochemical studies have indicated that such differential recognition can be explained by alterations in the primary structure of class I heavy chains. Characterization of these sequence differences may therefore identify portions of the class I molecule that form determinants recognized by CTL. In this study, we describe the cloning and sequencing of an HLA-A3 subtype from donor E1 (E1-A3). Cloning of the gene encoding E1-A3 was simplified by determining that a 15.5-kb BamHI fragment contains the complete gene and is characteristic of HLA-A3 and only one other class I gene (HLA-A11). Comparison of the E1-A3 sequence to that of a previously sequenced HLA-A3 gene for exons encoding extracellular class I domains revealed three nucleotide differences. All of these differences were located within a discrete region of exon 3 (encoding the alpha 2 domain) and result in a change of two amino acids, at positions 152 (Glu----Val) and 156 (Leu----Gln). This finding suggests that these amino acids are crucial for the information of a determinant recognized by CTL. Furthermore, the altered nucleotide sequence of E1-A3 is identical to the sequence of the HLA-Aw24 gene for codons 128 to 161. These observations of multiple clustered changes in the E1-A3 subtype (relative to the prototype sequence) and identity of the altered sequence with the sequence of another class I gene support the concept that gene conversion is a primary mechanism for the generation of class I polymorphism.
authors.forename: E P
authors.initials: EP
authors.lastname: Cowan
authors.forename: B R
authors.initials: BR
authors.lastname: Jordan
authors.forename: J E
authors.initials: JE
authors.lastname: Coligan
mesh_terms: D000328:Adult; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004274:DNA, Recombinant / Q000378:metabolism*; D005802:Genes, MHC Class II; D005815:Genetic Code; D006680:HLA Antigens / Q000145:classification / Q000235:genetics*; D015791:HLA-A3 Antigen; D006801:Humans; D007739:L Cells / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D011110:Polymorphism, Genetic; D013602:T-Lymphocytes, Cytotoxic / Q000145:classification* / Q000276:immunology / Q000378:metabolism
chemical_list: D004274:DNA, Recombinant; D006680:HLA Antigens; D015791:HLA-A3 Antigen; D004262:DNA Restriction Enzymes