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Title
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Identification of a novel HLA-B27 subtype by restriction analysis of a cytotoxic gamma delta T cell clone.
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Authors
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P.Del Porto,
M.D'Amato,
M.T.Fiorillo,
L.Tuosto,
E.Piccolella,
R.Sorrentino.
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Ref.
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J Immunol, 1994,
153,
3093-3100.
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PubMed id
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Abstract
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Seven HLA-B27 alleles are known, which share the same allospecificity, but
differ by one to six amino acid substitutions. Herein, we describe a novel
HLA-B27 allele, provisionally named B27-ci, which is expressed by an individual
from whom a B27-restricted gamma delta T cell clone has been derived. This clone
recognizes B cell lines from the proband and all of the other B27-positive
members of the family, but does not lyse B cell lines that express other HLA-B27
alleles. The amino acid sequence deduced from three B27-ci cDNA clones was found
to differ from the B*2705 sequence by one amino acid substitution (Asp to His)
in position 116 of the alpha 2 domain. This position has been shown to lie in
the floor of the F pocket, where it plays a key role in determining the nature
of the amino acid side chain that will fit into this pocket. Moreover, the fact
that the clone described here possesses a TCR-gamma delta indicates that this
subset of cells not only can be HLA-restricted, but also can finely discriminate
among classical class I molecules.
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