Antibody linker

The aP protein was denatured by the application of 10 pulses of 35 ps, 527 nm wavelength laser light of fluence 50mjcm however, when aP was indirectly coupled to the nanoparticle via an antibody linker (-5-10 run long), irradiation of the particle system with the same parameters did not cause protein inactivation. Subsequently, questions arose as to whether the linker was inactivated rather than the protein of interest, which would result in aP becoming dissociated from the linker. However, the conclusion was reached that the aP protein would not diffuse away from the particle by any appreciable distance during the nanosecond long... 

As shown in Table 2, free DAS, as expected, is its own best displacing agent, whereas only DAS—HMS showed any appreciable displacing capabiUty. This can be expected because the hemisuccinate linker is also immunogenic and leads to the production of antibodies specific for the linker in the polyclonal antibody population. AH the other toxins had at least lOOx less the avidity for the antibody, illustrating the specificity of the aDAS for DAS. 

A peptide linker-chelate analog, glycyl-tyrosyl-lysine-N-e-DTPA (GYK-DTPA), was incorporated onto B72.3 antibody and labeled with 11 In and 90y.81,82 In vitro and in vivo evaluations in dogs were conducted. Results indicated that the 11 in chelate was stable in vivo however, the 90Y version showed a biphasic decay pattern. The covalent bond between the peptide and DTPA precluded use of one of the coordinating arms that is necessary to coordinate 90Y in a stable fashion. 

Using the same versatile modular synthetic strategy, the same group developed biotinylated bi- (438) and tetra-antennary (439) mannosylated glycoconjugates to capture and detect E. coli cells, and compared the relative capturing ability of these molecules to commercial polyclonal antibodies (Fig. 47).318 Instead of aliphatic spacers, tetraethylene glycol linkers were used to diminish nonspecific binding and to impart flexibility for a better fit in the active sites. 

A-chain immunotoxins, however, may not be quite as cytotoxic as conjugates formed from intact toxin molecules (Manske et al., 1989). In an alternative approach to A chain use, the intact toxin of two-subunit proteins is directly conjugated to a monoclonal without isolation of the A chain. Conjugation of an antibody with intact A-B chain toxins can be done without a cleavable linker, as long as the A chain can still separate from the B chain once it is internalized. Therefore, it is important to avoid intramolecular crosslinking during the conjugation process which can prevent release of the A-B complex. In addition, since the B chain... 

Ballmer-Hofer, K., Schlup, V., Burn, P., and Burger, M.M. (1982) Isolation of in situ cross-linked ligand-receptor complexes using an anticross-linker specific antibody. Anal. Biocbem. 126, 246-250. 

Roberts, J.C., Adams, Y.E., Tomalia, D., Mercer-Smith, J.A., and Lavallee, D.K. (1990) Using starburst dendrimers as linker molecules to radiolabel antibodies. Bioconjugate Chem. 1(5), 305-308. 

Figure 4. (a) Selected residues from the combining site of antibody 5C8 com-plexed to piperidine-A/-oxide hapten 4, as determined by X-ray crystallography.1151 The linker portion of the hapten has been truncated to a methyl for comparison with the theozyme complex, (b) The formate/formic acid theozyme complexed to the model of hapten 4, as optimized through quantum mechanical calculations.161... 

Single-chain antibody (scFv) Comprises a VL linked to a VH chain via a polypeptide linker. It is thus a univalent functioning antibody containing both of the variable regions of the parent antibody. 

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