Monoclonal antibodies humanized mouse

Ibritumomab is a murine IgGi anti-CD20 antibody, the parent of the engineered chimeric antibody rituximab, a monoclonal antibody with mouse variable and human constant regions. It induces apoptosis and has antiproliferative effects. Ibritumomab tiuxetan (Zevalin) is composed of the monoclonal antibody ibritumomab, the linking chelator tiuxetan, and the radioisotope yttrium (1). 

Kennel, S. J., Falcioni, R and Wesley, J. W. (1991) Microdistribution of specific rat monoclonal antibodies to mouse tissues and human tumour xenografts. Cancer Res. 51,1529-1536. 

The pioneering work on monoclonal antibodies against TNF-a originate from Junming Le and Jan VUcek at the New York University School of Medicine. Infliximab (Retnicade ) is a chimeric, monoclonal anti-TNF-a-antibody (human/ mouse), which is approved for the treatment of rheumatoid arthritis, Crohn s disease (a chronic inflammatory disease of the intestine) and psoriasis. [210]... 

Mapping of hpoprotein particles was obtained mainly with monoclonal antibodies. Stable mouse or rat hybridoma ceU lines have been developed in our laboratory, in collaboration with others, to produce monoclonal antibodies against human apolipoproteins B, A-I, A-II, C-III, E, and (a). 

Monoclonal antibodies (mAh) are molecules that recognize and bind a specific foreign substance called an antigen. They are produced from a single clone of B lymphocytes. Conventionally, mouse mAh have been generated for experimental and diagnostic use. Techniques have been developed to humanize mouse mAh to facilitate their therapeutic use in humans. It is also now possible to make mAh which are fully human. 

Humanized Monoclonal Antibodies. Figure 1 Schematic representation of mouse, human, chimeric and... 

Anticytokine antibodies Infliximab Chimeric (mouse/human) monoclonal antibody against TNEa. Effective in the treatment of severe forms of rheumatoid arthritis where it can halt disease progression, or inflammatory bowel disease (EBD). 

The first mouse monoclonal antibody specific for human CD3 was produced in 1979 and named orthoclone OKT3. Aside from its use in the laboratory, OKT3 became the first anti-CD3 antibody to be utilized in transplantation medicine, but its wider application was hampered by its immunogenic and mitogenic properties (reviewed in [6]). Consequently, humanized and engineered anti-CD3 antibodies were developed to circumvent these limitations (Table 1). Since T cells and the TCR are involved in many immunological diseases, it is not surprising that the application of CD3 antibodies is not restricted to the field of transplantation. For example, CD3 antibodies are tested in clinical studies of diseases such as autoimmune diabetes (type 1 diabetes), immune-mediated inflammatory arthritis and inflammatory bowel disease [7]. 

Rituximab is a recombinant mouse/human chimeric monoclonal antibody whose in vitro activity varies with the number of terminal galactose moieties glycosylated to the peptide backbone at residue asparagine 301 [8]. The ability to monitor the levels of each discrete species present would allow the manufacturing process to... 

The most promising types of biologic response modifiers are monoclonal antibodies, cytokines, and fusion proteins.1 Monoclonal antibodies may be chimeric (fused mouse and human segments designated -ximab ), humanized with intermittent murine sequences (designated -zumab ), human backbone with monkey sequences, or fully human.40... 

Trastuzumab (Herceptin) -humanized mouse monoclonal antibody directed against HER-2/new receptor -fevers, chills, nausea, vomiting, headache during administration -cardiotoxicity (the FDA has not approved concurrent use with doxorubicin)... 

For other plant-derived antibodies, stability was shown to be similar to mammalian counterparts. For instance, a humanized anti-herpes simplex virus monoclonal antibody (IgGl) was expressed in soybean and showed stability in human semen and cervical mucus over 24 h similar to the antibody obtained from mammalian cell culture. In addition, the plant-derived and mammalian antibodies were tested in a standard neutralization assay with no apparent differences in their ability to neutralize HSV-2. As glycans may play a role in immune exclusion mechanisms in mucus, the diffusion of these monoclonal antibodies in human cerival mucus was tested. No differences were found in terms of the prevention of vaginal HSV-2 transmission in a mouse model, i.e. the plant-derived antibody provided efficient protection against a vaginal inoculum of HSV-2 [58]. This shows that glycosylation differences do not necessarily affect efficacy. 

The antibody preparations could be administered unaltered or (more commonly) after their conjugation to radioisotopes or toxins. Binding of unaltered monoclonal antibodies to a tumour surface alone should facilitate increased destruction of tumour cells (Figure 13.4). This approach, however, has yielded disappointing results, as the monoclonal antibody preparations used to date have been murine in origin. The Fc region of such mouse antibodies is a very poor activator of human immune function. Technical advances, allowing the production of human/humanized monoclonals (see later) may render this therapeutic approach more attractive in the future. 

Antibody immunogenicity remains one of the inherent therapeutic limitations associated with administration of murine monoclonals to human subjects. In most instances, a single injection of the murine monoclonal will elicit an immune response in 50-80 per cent of patients. Human anti-mouse antibodies (HAMA) will generally be detected within 14 days of antibody administration. Repeated administration of the monoclonal (usually required if the monoclonal is used for therapeutic purposes) will increase the HAMA response significantly. It will also induce an HAMA response in the majority of individuals who display no such response after the initial injection. The HAMA response will effectively and immediately destroy subsequent doses of monoclonal administered. In practice, therefore, therapeutic efficacy of murine monoclonals is limited to the first and, at most, the second dose administered. 

Bevacizumab, a recombinant, humanized monoclonal antibody, neutralizes vascular endothelial growth factor. The addition of bevacizumab to doublet chemotherapy is recommended in advanced NSCLC of nonsqua-mous cell histology in patients with no history of hemoptysis and no CNS metastasis who are not receiving therapeutic anticoagulation. 

There are literally hundreds of markers that are currently available for the mouse and human than can be used to characterize lymphoid and myeloid cells and subsets in primary and secondary lymphoid organs. Many of the markers expressed in mammals are highly conserved across species and have been designated as genetic clusters of differentiation (CD). CDs can be identified with fluorescently labeled monoclonal antibodies. As presented previously, when combined with other fluorescent probes, important information on intracellular biochemistry and cell function can be obtained. Many of the biochemical markers used by immunotoxicologists are common to other... 

Siegel, S.A. et al., The mouse/human chimeric monoclonal antibody cA2 neutralizes TNF in vitro and protects transgenic mice from cachexia and TNF lethality in vivo, Cytokine, 7, 26, 1995. 

Reff, M.E. et al., Depletion of B cells in vivo by chimeric mouse human monoclonal antibody to CD20, Blood, 83, 435, 1994. 

Incubate with mouse antibodies (in the case of Inada et al. (22) it was mous e monoclonal antibodies raised against human single- and double-stranded DNA) at a dilution of 1 10 in blocking buffer for 1 h at 37°C. 

Since a monoclonal antibody is a fusion product of a malignant mouse cell and an antibody-producing cell, there is some concern about the safety of the production process itself (Petricciani, 1983). Methods for the production of monoclonal antibodies raise two general safety issues (1) the theoretical risk of transferring in the product factors associated with malignancy (e.g., oncogene factors) and (2) the use of animals for antibody production that are known to harbor a number of microbial agents some of which can produce diseases in humans. 

This approach appears somewhat irrational and without much scientific merit, since many of these new molecules are minimally toxic or nontoxic by this sort of acute evaluation. As in the case of interferons or monoclonal antibodies, the toxic effects observed in humans might not be predicted from safety assessments in rodents. An appropriate test species should be selected. Is the rat or mouse the appropriate species to evaluate a species-specific rDNA protein such as human growth hormone or interferons, or would nonhuman primates be more suitable Does the nonhuman primate really offer any advantages There is some consensus that the nonhuman primate may be a more appropriate species for testing some rDNA human proteins. 

---