Antibodies charge-modified

ENHANCING IN VIVO TARGETED DRUG DELIVERY WITH NEGATIVE CHARGE-MODIFIED MONOCLONAL ANTIBODIES... 

Khaw, B.A. Klibanov, A. O Dormell, S.M. Saito, T. Nossiff, N. Slinkin, M.A. Newell, J.B. Strauss, H.W. Torchihn, V.P. Gamma imaging with negatively-charge-modified monoclonal antibody modification with synthetic polymers. J. Nucl. Med. 1991, 32, 1742-1751. 

Narnia, J. Petrov, A. Ditlow, C. Pak, K.Y. Chen, F.W. Khaw, B.A. Maximizing radiotracer dehvery for scintigraphic localization of experimental atherosclerotic lesions with high-dose negative-charge-modified Z2D3 antibody. J. Nucl. Cardiol. 1997, 4, 226-233. 

FA Chen. Characterization of charge-modified and fluorescein- labeled antibody by capillary electrophoresis using laser-induced fluorescence. Application to immunoassay of low level immunoglobulin A. J Chromatography 680 419-423,... 

Raising the pi of macromolecules also can significantly alter the immune response toward them upon in vivo administration. Cationized proteins (those modified with diamines to increase their net charge or pi) are known to generate an increased immune response compared to their native forms (Muckerheide et al., 1987a, b Apple et al., 1988 Domen et al., 1987 Domen and Hermanson, 1992). The use of cationized BSA as a carrier protein for hapten conjugation can result in a dramatically higher antibody response toward a coupled hapten (Chapter 19). 

Maehashi et al. (2007) used pyrene adsorption to make carbon nanotubes labeled with DNA aptamers and incorporated them into a field effect transistor constructed to produce a label-free biosensor. The biosensor could measure the concentration of IgE in samples down to 250 pM, as the antibody molecules bound to the aptamers on the nanotubes. Felekis and Tagmatarchis (2005) used a positively charged pyrene compound to prepare water-soluble SWNTs and then electrostatically adsorb porphyrin rings to study electron transfer interactions. Pyrene derivatives also have been used successfully to add a chromophore to carbon nanotubes using covalent coupling to an oxidized SWNT (Alvaro et al., 2004). In this case, the pyrene ring structure was not used to adsorb directly to the nanotube surface, but a side-chain functional group was used to link it covalently to modified SWNTs. 

The bait and switch methodology deploys a hapten to act as a bait . This bait is a modified substrate that incorporates ionic functions intended to represent the coulombic distribution expected in the transition state. It is thereby designed to induce complementary, oppositely charged residues in the combining site of antibodies produced by the response of the immune system to this hapten. The catalytic ability of these antibodies is then sought by a subsequent switch to the real substrate and screening for product formation, as described above. 

The MALDI mass spectrum obtained from the peptides resulting from the enzymatic digestion (Asp-N) of the bFGF protein (A) spectrum before and (B) spectrum after immunoprecipitation with an antibody directed against the recombinant protein. The peaks marked correspond to either Cu adducts or doubly charged ions. (C) Schematic representation of the observed peptides. A continuous line corresponds to a peptide that links to the antibody, and a dotted line to a peptide that does not link. Reproduced (modified) from Zhao Y.M., Muir T.W., Kent S.B.FL, Tisher E., Scardina J.M. and Chait B.T., Proc. Natl. Acad. Sci. USA, 93, 4020M024, 199, with permission. 

Fig. 5 NRL Array Biosensor mixed format immunoassays (modified from [119]). Schematic of (a) the sandwich and (b) the competitive immunoassay fonnats used in the detection of the Campylobacter jejuni and aflatoxin Bi (AFBi), respectively, (a) Sandwich format antigen captured by the immobilized antibody then quantified by passing a second, fluorescently labeled, antibody over the surface, (b) Competitive format competition for binding sites on the fluorescently labeled antibody occurs between the unlabeled antigen in solution and the surface-bound antigen analog, (c) Final charge-coupled devices image taken with the NRL Array Biosensor of a waveguide exposed simultaneously to the C. jejuni (5 x 10" cfu/mL) sandwich assay (SAND) and the aflatoxin Bj (AFBi-1 ng/mL) competitive assay (COMP) in various combinations...

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