Abstract
The mouse thymic leukemia (TL) Ag is a nonclassical MHC class I molecule that binds with higher affinity to CD8alphaalpha than CD8alphabeta. The interaction of CD8alphaalpha with TL is important for lymphocyte regulation in the intestine. Therefore, we studied the molecular basis for TL Ag binding to CD8alphaalpha. The stronger affinity of the TL Ag for CD8alphaalpha is largely mediated by three amino acids on exposed loops of the conserved alpha3 domain. Mutant classical class I molecules substituted with TL Ag amino acids at these positions mimic the ability to interact with CD8alphaalpha and modulate lymphocyte function. These data indicate that small changes in the alpha3 domain of class I molecules potentially can have profound physiologic consequences.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Amino Acid Substitution
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Animals
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Base Sequence
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Binding Sites / genetics
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CD8 Antigens / chemistry
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CD8 Antigens / genetics
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CD8 Antigens / metabolism*
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Conserved Sequence
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DNA / genetics
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Humans
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Hybridomas
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In Vitro Techniques
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Membrane Glycoproteins / chemistry
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Membrane Glycoproteins / genetics
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Membrane Glycoproteins / metabolism*
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Mice
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Mice, Inbred C57BL
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Models, Molecular
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Molecular Sequence Data
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Protein Structure, Tertiary
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Sequence Homology, Amino Acid
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T-Lymphocytes / immunology
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Transfection
Substances
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CD8 Antigens
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CD8 antigen, alpha chain
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Membrane Glycoproteins
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Recombinant Proteins
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thymus-leukemia antigens
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DNA