Analysis of gene structure and antigen determinants of DR2 antigens using DR gene transfer into mouse L cells.
Three HLA class II DR beta genes and one DR alpha gene from the DR2 haplotype were cloned in cosmid vectors. The DR beta II gene might be a pseudogene lacking the first exon that encodes the leader peptide. The DR beta I and DR beta III genes were expressed, together with the DR alpha-chain, after transfection into mouse L cells. Restriction enzyme mapping of the DR beta genomic clones and reactivity of their products expressed on the L cell transfectant against mAb showed that the DR beta I and DR beta III genes encoded the nonpolymorphic and polymorphic DR beta chain, respectively. This arrangement is the reverse of that observed in other haplotypes, such as DR3, 4 and 6. The alignment of the HLA class II genes including the DR beta genes on the chromosome 6, however, was consistent with other haplotypes, e.g., centromere-DX beta-DX alpha-DV beta-DQ beta-DQ alpha-DR beta I-DR beta II- DR beta III-DR alpha-telomere. These results suggest that the susceptibility to mutations or gene conversions responsible for genetic polymorphisms depends on the gene itself and not on its location. Furthermore, absorption experiments of anti-DR2 allosera by the DR alpha/DR beta transfectants revealed that the so-called DR2 specificities were determined by multiple epitopes although both the DR beta I and DR beta III genes behaved similarly with DR2-specific antibodies.
Kawai
J
J
Department of Transplantation, Tokai University School of Medicine, Kanagawa, Japan.
Ando
A
A
Sato
T
T
Nakatsuji
T
T
Tsuji
K
K
Inoko
H
H
D000042:Absorption; D000818:Animals; D002874:Chromosome Mapping; D002896:Chromosomes, Human, Pair 6; D003001:Cloning, Molecular; D003601:Cytotoxicity Tests, Immunologic; D000939:Epitopes / Q000032:analysis*; D005802:Genes, MHC Class II; D006684:HLA-DR Antigens / Q000032:analysis / Q000235:genetics*; D015802:HLA-DR2 Antigen; D006801:Humans; D007739:L Cells / Q000032:analysis*; D051379:Mice; D011110:Polymorphism, Genetic; D014162:Transfection
D000939:Epitopes; D006684:HLA-DR Antigens; D015802:HLA-DR2 Antigen