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1996-02-27
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Document 0661
DOCN M9630661
TI CDR walking mutagenesis for the affinity maturation of a potent human
anti-HIV-1 antibody into the picomolar range.
DT 9603
AU Yang WP; Green K; Pinz-Sweeney S; Briones AT; Burton DR; Barbas CF 3rd;
Department of Molecular Biology, Scripps Research Institute, La; Jolla,
CA 92037, USA.
SO J Mol Biol. 1995 Dec 1;254(3):392-403. Unique Identifier : AIDSLINE
MED/96095799
AB We describe the investigation of methodologies for the creation of very
high affinity human antibodies. The high affinity human antibody b4/12
was optimized for its affinity to the human envelope glycoprotein gp120
of human immunodeficiency virus type 1 (HIV-1). Five libraries of b4/12
were constructed by saturation mutagenesis of
complementarity-determining regions (CDRs). Libraries of antibody Fab
fragments were displayed on the surface of filamentous phage and
selected in vitro for binding to immobilized gp120. Sequential and
parallel optimization strategies of CDRs were examined. The sequential
CDR walking strategy consistently yielded b4/12 variants of improved
affinity in each of the four different optimization sequences examined.
This resulted in a 96-fold improvement in affinity. Additivity effects
in the antibody combining site were explored by combining independently
optimized CDRs in the parallel optimization strategy. Six variants
containing optimized CDRs were constructed. Improvement of affinity
based on additivity effects proved to be unpredictable but did lead to a
modest improvement in affinity. Indeed, only one of the six combinations
demonstrated additivity. The highest affinity Fab prepared using this
strategy was improved 420-fold in affinity. The affinity of this Fab was
15 pM as compared to 6.3 nM for b4/12. Examination of the kinetics of
Fab binding to gp120 revealed that improvements in affinity were
dominated by a slowing of the off-rate of the Fab. The methodology
presented here provides a route for the improvement of the affinities of
antibodies typical of tertiary immune responses into the picomolar
range. Such improvements may have profound effects on the utility of
antibodies as therapeutic and prophylactic agents.
DE Amino Acid Sequence Antibody Affinity/*GENETICS Antigen-Antibody
Reactions Bacteriophages/GENETICS Base Sequence Binding Sites,
Antibody/*GENETICS Comparative Study Gene Library HIV
Antibodies/*GENETICS/IMMUNOLOGY HIV Envelope Protein gp120/*IMMUNOLOGY
HIV-1/*IMMUNOLOGY Immunoglobulins, Fab/GENETICS Immunoglobulins,
Heavy-Chain/GENETICS Immunoglobulins, Light-Chain/GENETICS Models,
Molecular Molecular Sequence Data *Mutagenesis Support, Non-U.S.
Gov't Support, U.S. Gov't, P.H.S. JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).