RG1, a new murine monoclonal antibody recognizing a "supertypic" determinant on HLA-A molecules.
Monomorphic and polymorphic anti-HLA monoclonal antibodies (mAb) are valuable reagents for assessment of the structural and functional importance of different class I determinants. We have generated a new mAb, RG1, reacting with an epitope variably expressed on normal and leukemic hematopoietic cells of different lineages. Immunoprecipitation of the RG1 antigen disclosed a bimolecular complex characteristic of class I proteins. The RG1 epitope was expressed on an HLA-A2 transfected cell line but not on cells transfected with HLA-E, -F or -G molecules. MAb reactivity with reference B-lymphoblastoid cell lines and HLA typing of RG1 reactive and unreactive cells demonstrated that the epitope was expressed in conjunction with defined HLA-A molecules. Cells expressing HLA-A2, -A24(9) and -A68(28) proteins were brightly stained with RG1 whereas mAb binding to HLA-A1, -A11 and a split of A3 molecules was significantly lower. In contrast, the RG1 epitope was apparently not expressed on HLA-A23(9), -A25(10), -A26(10), -A29(19), -A30(19), -A31(19), -A32(19), -A33(19) and some HLA-A3 molecules. Based on class I alpha sequence data, these results suggest that the RG1 epitope is localized to a region of the alpha 2 helix accessible to the T cell receptor for antigen on cytotoxic T lymphocytes. Lys in position 144 and His in position 151 are apparently critical for RG1 binding.
Pettersen
R D
RD
Department of Pediatric Research, National Hospital, Oslo, Norway.
Hestdal
K
K
Lee
N
N
Geraghty
D E
DE
Valø
E T
ET
Lie
S O
SO
Gaudernack
G
G
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000937:Antigen-Antibody Reactions / Q000276:immunology*; D001666:Binding Sites, Antibody / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D002478:Cells, Cultured; D000939:Epitopes / Q000032:analysis / Q000276:immunology*; D015234:HLA-A Antigens / Q000032:analysis / Q000276:immunology*; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data
D000911:Antibodies, Monoclonal; D000939:Epitopes; D015234:HLA-A Antigens