Bispecific antibody

Fig. 7.1. Principles of tumor cell kill by antibodies bispecific antibody-mediating effector-tumor cell interaction, naked antibody mediating antibody dependent cellular cytotoxicity...

Antibody targeting Use of mono-and bispecific antibodies to target components of angiogenic blood vessels (e.g., VEGF receptors, endoglin, L19 antigen) to deliver specific angio- and/or tumoricidal activity... 

Hollinger, P., Prospero, T., and Winter, G. (1993). "Diahodies" Small bivalent and bispecific antibody fragments. Proc. Natl. Acad. Sci. USA 90, 6444-6448. 

SATA has been used to form conjugates with avidin or steptavidin with excellent retention of activity (Chapter 23, Section 3.1). It also has been used in the formation of a therapeutically useful toxin conjugate with recombinant CD4 (Ghetie et al., 1990), to study syntaxin proteins (Amessou et al., 2007), to prepare bispecific antibodies (Lindorfer et al., 2001), and to make a unique polylysine conjugate as a vehicle for drug delivery (Sakharov et al., 2001). 

In a comparative study of disulfide reducing agents, it was determined that use of the relatively strong reductants DTT and TCEP required only 3.25 and 2.75 mole equivalents per mole equivalent of antibody molecule to achieve the reduction of two interchain disulfide bonds between the heavy chains of a monoclonal IgG (Sun et al., 2005). This limited reduction strategy retains intact bispecific antibody molecules while providing discrete sites for conjugation to thiols. 

The following protocol is based on the methods recommended by Thermo Fisher for use of the cyanine dye DyLight 649. Antibody reduction is based on the methods of Sun et al. (2005), which results in partially reduced bispecific immunoglobulin containing available thiols in the hinge region for labeling. 

Polyclonal antibodies can react with many epitopes, whereas MAbs are restricted to one epitope on proteins that do not have repeating sequences.24 By definition, polyclonal immunoassays are generally much more sensitive but less specific than monoclonal assays. Bispecific or hybrid antibodies can be used to increase the affinity. Bispecific antibodies are formed by the fusion of two previously established hybridomas to produce antibodies displaying the binding characteristics of both of the antibodies in one molecule.25... 

Another variation to conjugate antibodies is to use bispecific antibodies. These are produced using chemical means and recombinant techniques to fuse separate hybridomas into a hybrid hybridoma (Fig. 4.6). Bispecific antibodies use one arm of the Fv to target the antigen or tumor cell and the other arm carries the effector molecule of toxins, radioisotopes, or other drugs. 

Bispecific monoclonal antibodies (BsMAb) which combine the specificity of two different antibodies within one molecule and cross-link an effector cell or a toxic molecule with the target cell (Section 8.5.2). 

Another approach to selectively inducing tumour cell kilhng is by the use of bispecific monoclonal antibodies (BsMAb).They combine the specificity of two separate antibodies within one molecule and cross-hnk an effector killer cell or a toxic molecule with the target cell to be destroyed [75]. There are three major approaches for creating BsMAbs.They can be obtained by chemical cross-linking of two MAbs, by fusing two hybridomas [76], or by genetic... 

Figure 9.3. Photograph of a mouse 7 days after i.v. injection of a coaguligand formulation consisting of truncated Tissue Factor mixed with a bispecific antibody directed at the MHC Class II molecules on the tumour vasculature and at truncated Tissue Factor. The mouse carried a C1300 muy tumour measuring approximately 10 x 10 mm in diameter at the time of treatment. Within hours after treatment the tumour blood flow was blocked by generalized blood coagulation in the tumour vasculature (not shown). Seven days after treatment, the necrotic tissue was almost completely removed by the host immune cells.

Kufer P, Lutterbiise R, Baeuerle PA. A revival of bispecific antibodies. Trends Biotechnol 2004 22 238 4. 

Improving Antibody Function Using Bispecific Antibodies... 

TABLE 10.7. Some examples of bispecific antibodies (BsAb) in clinical trials... 

Staerz, U.D., and M.J. Bevan, Hybrid hybridoma producing a bispecific monoclonal antibody that can focus effector T-cell activity. Proc Natl Acad Sci USA, 1986. 83(5) 1453-7. 

Mezzanzanica, D., S. Canevari, S. Menard, S.M. Pnpa, E. Tagliabue, A. Lanzavecchia, and M.I. Colnaghi, Human ovarian carcinoma lysis by cytotoxic T cells targeted by bispecific monoclonal antibodies analysis of the antibody components. Int J Cancer, 1988. 41(4) 609-15. 

Gilliland, L.K., M.R. Clark, and H. Waldmann, Universal bispecific antibody for targeting tumor cells for destruction by cytotoxic T cells. Proc Natl Acad Sci USA, 1988. 85(20) 7719-23. 

Nitta, T, K. Sato, K. Okumura, and S. Ishii, Induction of cytotoxicity in human T cells coated with anti-glioma x anti-CD3 bispecific antibody against human glioma cells. J Neurosurg, 1990. 72(3) 476-81. 

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