Monoclonal antibodies evaluation

To study the role of lysine residues in susceptibility to formalin fixation, the amino acid composition of immunoreactive peptides (to various monoclonal antibodies) was studied. Each peptide was evaluated to determine if immu-noreactivity was lost after formalin fixation. Formalin sensitivity was correlated with the peptides amino acid composition. The first step in the method is biopanning from a peptide combinatorial library with a monoclonal antibody. The peptides that bind to the antibody were tested for their sensitivity to formalin fixation. Some peptides remain immunoreactive whereas others do not. The peptides were then sequenced to look for differences between those that were sensitive to formaldehyde versus those that were not. The goal was to find whether there is a particular amino acid that is present in formalin-sensitive epitopes but absent in formalin-resistant epitopes, or vice versa. An advantage of this approach is that it is open-ended, without excluding any amino acids. 

Barth, R.F., Adams, D.M., Soloway, A.H., Alam, F., and Darby, M.V. (1994) Boronated starburst den-drimer-monoclonal antibody immunoconjugates Evaluation as a potential delivery system for neutron capture therapy. Bioconjugate Chem. 5, 58-66. 

Kobayashi, H., Wu, C., Kim, M.K., Paik, C.H., Carrasquillo, J.A., and Brechbiel, M.W. (1999) Evaluation of the in vivo biodistribution of indium-111 and yttrium-88 labeled dendrimer-1 B4M-DTPA and its conjugation with anti-Tac monoclonal antibody. Bioconjug. Chem. 10, 103-111. 

Thus, the tetravalency, anti-inflammatory properties and molecular stability of slgA make it particularly suitable for protective passive immunity when applied to mucosal surfaces. To date, the clinical evaluation of slgA protection in humans and animal models has been very limited. Indeed most studies have employed monomeric IgA monoclonal antibodies [3,15]. Hence, differences in IgA and IgG protective activities at the mucosal level have often not been observed [15]. Only a few studies have demonstrated the superior activity of polymeric IgA or slgA compared with monomeric IgG or IgA [16]. In order to determine the efficacy of slgA, future animal experiments and clinical trials are needed to compare the activities of IgG monoclonal antibodies and their slgA counterparts. The ability to engineer slgAs in plants will allow these comparisons to be made [17]. 

After the approval of the first product, recombinant insulin, in 1982, progress in the development of new recombinant protein pharmaceuticals was slow ([10], Fig. 17.1). The number of biotechnology-derived drugs and vaccines approved by the US Food and Dmg Administration (FDA) has increased significantly only since 1995. More recently, sales of biologies have skyrocketed, e.g. from 900 million in 1999 to an estimated 3.5 billion in 2001 for monoclonal antibodies [11]. The annual global market for biopharmaceuticals is estimated to have increased from 12 billion US to 30 billion US in 2003 [12]. 500 candidate biopharmaceuticals are undergoing clinical evaluation and over one hundred protein-based therapeutics are in the... 

At least 1000 potential biopharmaceuticals are currently being evaluated in clinical trials, although the majority of these are in early stage trials. Vaccines and monoclonal antibody-based products represent the two biggest product categories. Regulatory factors (e.g. hormones and... 

Umemura, S., Sekido, Y., Itoh, H., and Osamura, RY. 2002. Pathological evaluation of HER2 overexpression for the treatment of metastatic breast cancers by humanized anti-HER2 monoclonal antibody (trastuzumab). Acta Histochemica et Cytochemica, Kyoto 35(2), 77-81. 

Priliximab (cM-T412) is an anti-CD4 chimeric monoclonal antibody that was evaluated in the clinic for the treatment of autoimmune diseases. Priliximab binds to CD4 on the surface of T cells and leads to a profound and sustained decrease in circulating CD4+ T cells decreased counts have been reported to be below normal levels at 18 and 30 months following single- and multiple-infusions.81 Similar findings were observed in preclinical studies in chimpanzees.82 The administration of priliximab was also associated with a cytokine-release syndrome that caused transient fever, myalgia, chills, headache, nausea, and/or hypotension that was accompanied by an increase in serum IL-6. Although evidence of efficacy was observed in clinical trials for CD, the... 

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. 

It has also been proposed that new monoclonal antibodies be first examined by immunohistochemistry in several dilutions of twofold increments beyond those generally recommended by vendors, using 0.05 M Tris buffers of pH 6.0 and 8.6 without NaCl. Thereby, many monoclonal antibodies could be used in dilutions up to eightfold higher than those recommended by the vendor (Boenisch 1999). To the time of this writing, we have not yet had the opportunity to evaluate this apparently interesting approach. 

Center for Biologies Evaluation and Research. Guidance for Industry Monoclonal Antibodies Used as Reagents in Drug Manufacturing, FDA, RockviUe, MD, 2001. 

Manil, L., Motte, P., Pernas, P., Troalen, F. Bohuon, C., and Belief D. (1986) Evaluation of protocols for purification of mouse monoclonal antibodies. J. Immunol. Methods 90, 25-37. 

It is entirely possible that surface staining cannot be accomplished before fixation. Some antibody-antigen complexes cannot withstand chemical fixation and/or permeabilization. An empirical evaluation must be made. In this example, cells are first stained with a monoclonal antibody against a cell-surface receptor, fixed with ethanol, and then the DNA is stained with propidium iodide. The cells are analyzed for two-color fluorescence, the green of the fluorescein-labeled surface marker and the red of the labeled DNA intercalator. This approach works for antibody-antigens that are unaffected by fixation. 

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