Abstract
We present here the molecular characterization of a new activation-induced surface structure on human T lymphocytes, termed LA45, with high homology (93% at protein level) to MHC class I molecules. Antigen modulation and sequential immunoprecipitation experiments revealed that LA45 and HLA class I proteins do not crossreact with the corresponding antibodies. Furthermore, LA45 is not associated with beta 2-m. On the other hand, we could show that the separation of HLA-A,B,C and beta 2m molecules, induced by SDS-denaturation, leads to a conformational change in the heavy chain in such a way that it becomes reactive with LA45. The 90/45 kD LA45 proteins thus appear to be non-beta 2m-associated MHC class I alpha chains that are selectively expressed by activated but not by resting human T lymphocytes.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Antibodies, Monoclonal
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Antigens, CD / analysis*
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Antigens, Differentiation, T-Lymphocyte / analysis
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Base Sequence
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Blotting, Western
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CD3 Complex
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Cells, Cultured
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Cloning, Molecular
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Histocompatibility Antigens Class I / analysis*
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Histocompatibility Antigens Class I / genetics
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Humans
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Lymphocyte Activation*
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Macromolecular Substances
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Molecular Sequence Data
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Receptors, Antigen, T-Cell / analysis
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Sequence Homology, Nucleic Acid
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T-Lymphocytes / immunology*
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beta 2-Microglobulin / analysis*
Substances
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Antibodies, Monoclonal
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Antigens, CD
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Antigens, Differentiation, T-Lymphocyte
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CD3 Complex
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Histocompatibility Antigens Class I
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LA45 antigen
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Macromolecular Substances
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Receptors, Antigen, T-Cell
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beta 2-Microglobulin