| 1. |
- Faber, Catherine, et al.
(författare)
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Three-dimensional structure of a human Fab with high affinity for tetanus toxoid
- 1998
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Ingår i: Immunotechnology. - 1380-2933. ; 3:4, s. 253-270
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Tidskriftsartikel (refereegranskat)abstract
- Background: The wide range of antibody specificity and affinity results from the differing shapes and chemical compositions of their binding sites. These shapes range from discrete grooves in antibodies elicited by linear oligomers of nucleotides and carbohydrates to shallow depressions or flat surfaces for accommodation of proteins: peptides and large organic compounds. Objectives: To determine the Fab structure of a high-affinity human antitoxin antibody. To explore structural features which enable the antibody to bind to intact tetanus toxoid, peptides derived from the sequence of the natural immunogen and antigenic mimics identified by combinatorial chemistry. To explain why this Fab shows a remarkable tendency to produce crystals consistently diffracting to d spacings of 1.7-1.8 Å. To use this information to engineer a strong tendency to crystallize into the design of other Fabs. Study design: The protein was crystallized in hanging or sitting drops by a microseeding technique in polyethylene glycol (PEG) 8000. Crystals were subjected to X-ray analysis and the three-dimensional structure of the Fab was determined by the molecular replacement method. Interactive computer graphics were employed to fit models to electron density maps, survey the structure in multiple views and discover the crystal packing motif of the protein. Results: Exceptionally large single crystals of this protein have been obtained, one measuring 5 x 3 x 2 mm (l x w x d). The latter was cut into six irregular pieces, each retaining the features of the original in diffracting to high resolution (1.8 Å) with little decay in the X-ray beam. In an individual Fab, the active site is relatively flat and it seems likely that the protein antigen and derivative peptides are tightly held on the outer surface without significant penetration into the interior. There is no free space to accommodate even a dipeptide between V(H) and V(L). One of the unique features of the B7-15A2 Fab is a large aliphatic ridge dominating the center of the active site. The CDR3 of the H chain contributes significantly to this ridge, as well as to adjoining regions projected to be important for the docking of the antigen. Both the ease of crystallization and the favorable diffraction properties are mainly attributable to the tight packing of the protein molecules in the crystal lattice. Discussion: The B7-15A2 active site provides a stable and well defined platform for high affinity docking of proteins, peptides and their mimotopes. The advantages for future developments are suggested by the analysis of the crystal properties. It should be possible to incorporate the features promoting crystallization, close packing and resistance to radiation damage into engineered human antibodies without altering the desired specificities and affinities of their active sites.
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| 2. |
- Hansson, Ulla-Britt, et al.
(författare)
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Antigen-binding sites dominate the surface properties of antibodies
- 1996
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Ingår i: Immunotechnology. - 1380-2933. ; 2:4, s. 276-276
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Tidskriftsartikel (refereegranskat)abstract
- We have found a remarkable relationship between the specificity of antibodies and their chromatographic behavious upon liquid-liquid partition chromatography (LLPC). Well characterized human and murine monoclonal antibodies and Fab/Fv fragments thereof as well as mouse/human chimeric antibodies were employed. While, lgG 1, 2 and 4 antibodies with identical specificities (affinity constants) have identical partition properties, lgG antibodies with different partition properties reacted with different partition epitopes or had different affinities against the same epitope. Hence, the surface properties of the antigen binding sites dominate over all other surfaces of the free antibody molecule. LLPC may also be used to detect conformational changes occuring upon binding of antigen by antibody. Antigen-antibody complexes formed by different lgG antibodies against a large antigen like HSA all had similar surface properties. different from those of both antigen and antibody. In contrast, the surface properties of complexes formed by small antigens haptens are related to those of the lgG antibody. In addition, antigen-antibody complexes were found to have similar surface properties irrespective of the molar ratio of antigen to antibody at which the complexes had been formed.
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| 3. |
- Söderlind, Eskil, et al.
(författare)
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Complementarity-determining region (CDR) implantation : A theme of recombination
- 1999
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Ingår i: Immunotechnology. - 1380-2933. ; 4:3-4, s. 279-285
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Tidskriftsartikel (refereegranskat)abstract
- A novel technology in the area of antibody engineering has been developed which allows for the creation of new types of antibody molecules. It is called complementarity-determining region (CDR) implantation and permits the random combination of CDR sequences formed in vivo into a single master framework. Thus, totally new gene combinations can be produced and used in selection processes. The result is a genetic variability which is extremely large, even exceeding the natural variability found in the immune system. In this commentary, CDR implantation is presented and the technology is discussed.
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| 4. |
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| 5. |
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| 6. |
- Wahren, B
(författare)
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Gene vaccines
- 1996
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Ingår i: Immunotechnology : an international journal of immunological engineering. - : Elsevier BV. - 1380-2933. ; 2:2, s. 77-83
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Tidskriftsartikel (refereegranskat)
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