Monoclonal antibodies single-chain

Monsanto/ Agracetus Monoclonal antibodies, single chain antibodies, Human growth hormone (plastid), collagen 170-177... 

CP coat protein CtxB cholera toxin B subunit scFv single chain Fv antibody fragment TMOF trypsin modulating oostatic factor MAB monoclonal antibody GFP green fluorescent protein CPV Canine parvovirus BHV Bovine herpes virus FMDV Foot and mouth disease virus HCV Hepatitis C virus HRV Human rhino Virus MEV Mink enteritis virus MHV Murine hepatitis virus MV Measles virus RSV Respiratory syncytial virus... 

The total cDNA construct of NPN43C9 was expressed efficiently in E. coli cells and protein purified, and its catalytic properties were assessed in both the monoclonal antibody and the single-chain antibody (scFv) 7A4-1/212 for the hydrolysis of p-nitroanilide [50] and the related p-chlorophenyl ester [51a] (Fig. 19). Virtually identical kca, and Km values were obtained for both 7A4-1/212 and NPN43C9. This activity was decreased in both cases by the addition of the inhibitor w-nitroanilide [52], which gave K = 800 p.M and 400 pM for the NPN43C9 and 7A4-1/212, respectively. 

Milenic, D.E., Yokota, T., Filpula, D.R., Finkelman, M.A., Dodd, S.W., Wood, J.F. et al. (1991) Construction, binding properties, metabolism, and tumor targeting of a single-chain Fv derived from the pancarcinoma monoclonal antibody CC49. Cancer Res., 51, 6363-6371. 

Ricin is a type II toxin. The A chain (ricin A) contains 267 amino acid residues, and the B chain (ricin B) 262 residues. Ricin A is exceptionally toxic, and it has been estimated that a single molecule is sufficient to kill an individual cell. This peptide can be prepared by genetic engineering using Escherichia coli. The potent action of this material on eukaryotic cells has been investigated in anticancer therapy. Ricin A has been coupled to monoclonal antibodies and successfully delivered specifically to the tumour cells. However, in vitro toxicity of ricin A-based immunotoxins is enhanced significantly if ricin B is also present. 

Fig. 3.4 Modes of action of monoclonal antibodies in cancer therapy. scFv single-chain Fv fragment. (Reproduced from Carter, P. 2001. Improving the efficacy of antibody-based cancer therapies. Nat. Rev. Cancer1 118-129).

Sequential Transfection. A simple approach to boosting expression is to repeat the transfection on previously transfected cells but with selectable markers not used in the first transfection. Xoma (Berkeley, CA), Sunol Molecular (Miramar, FL), and ICOS (Bothell, WA) have used this approach successfully. Fivefold or greater improvements in expression can be achieved in a single sequential transfection. ICOS reports the added advantage of balancing heavy and light chain ratios to improve the secretion and expression of recombinant monoclonal antibodies. 

Affinity selection is by far the most important application of phage display (for practical reviews, see [4, 5]). Libraries of phage-displayed peptides are now commonly used to select peptides that bind to receptors or enzymes of therapeutic interest. The technology is also very powerful for the discovery of new monoclonal antibodies from collections of phages displayed single chain Fv or Fab fragments. 

Two monoclonal antibodies, one highly specific for human albumin (HSA-1) and one of broader specificity for several primates (HSA-2), were selected for subsequent use. These antibodies were purified by hydroxyapatite chromatography to single heavy- and light-chain bands (Figure 4) and then biotinylated. 

M., Addition of an extra immunoglobulin domain to two anti-rodent TNF monoclonal antibodies substantially increased their potency. Mol. Immunol. 41, 73-80, 2004 Adams, G.P., Tai, M.S., McCartney, J.E. et al.. Avidity-mediated enhancement of in vivo tumor targeting by single-chain Fv dimers, Clin. Cancer Res. 12, 1599-1605, 2006. 

Table 7 lists S-100-positive tumors and their positivity with additional markers. Myelin basic protein (MBP) (30) is a single-chain polypeptide associated with the central and peripheral nervous system. Glial fibrillary acidic protein (GFAP) and neurofilament proteins (NFP) are intermediate filaments associated with glial cells and neural cells, respectively. HMB-45 is a mouse monoclonal antibody that reacts with an antigen present in premelanosomes. It is highly sensitive and specific for melanomas and certain nevi (junctional, congenital, blue nevi). EMA has been discussed in Section 3.1.3.1. 

Monoclonal Antibodies An antibody is called monoclonal when each immunoglobulin is produced by a single clone of cells and hence is identical to every other molecule in the preparation, in terms of heavy as well as light chain structure. Thus they are highly specific and offer more consistent efficacy and predictable toxicity in vivo than the polyclonal counterparts. ... 

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