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Title
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Antibody engineering for the analysis of affinity maturation of an anti-hapten response.
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Authors
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D.Allen,
T.Simon,
F.Sablitzky,
K.Rajewsky,
A.Cumano.
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Ref.
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Embo J, 1988,
7,
1995-2001.
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PubMed id
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Abstract
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The influence of structural variation, previously observed in a panel of V186.2
VH/V lambda 1-expressing anti-NP antibodies from the secondary response, on the
affinity of these antibodies was examined by site-specific mutagenesis and
recombinant antibody construction. A tryptophan----leucine exchange at position
33 in the VH segment of all but one of the high-affinity antibodies is the most
frequently observed somatic mutation and by itself leads to a 10-fold higher
affinity; all other somatic exchanges are irrelevant for affinity selection. In
the single case of a high-affinity antibody without this common exchange, high
affinity is mediated by a combination of mutations (including a one-codon
deletion) in VH and the particular D-JH rearrangement carried by this antibody.
The data indicate that the pattern of somatic diversification through
hypermutation is shaped by affinity selection, but that only a single point
mutation is available in the VH and the VL gene of lambda 1 chain-bearing
anti-NP antibodies which by itself leads to an increase of hapten-binding
affinity. Based on the analysis of two secondary response antibodies from which
somatic mutations in VH and VL have been eliminated, it is also concluded that
the recruitment of B cell clones into the pathway of hypermutation involves a
mechanism which is not based upon affinity differences towards the antigen.
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