Antibodies derivatives

Another example of vims clearance is for IgM human antibodies derived from human B lymphocyte cell lines where the steps are precipitation, size exclusion using nucleases, and anion-exchange chromatography (24). A second sequence consists of cation-exchange, hydroxylapatite, and immunoaffinity chromatographies. Each three-step sequence utilizes steps based on different properties. The first sequence employs solubiUty, size, and anion selectivity the second sequence is based on cation selectivity, adsorption, and selective recognition based on an anti-u chain IgG (24). 

Immunosera and human immunoglobulins depend for their protective effects on their content of antibodies derived, in the case of immunosera, flxm immunized animals and, in the case of immunoglobulins, flxm humans who have been immunized or who have high antibody titres consequent upon prior infection. This form of immunity, known as passive immunity, is achieved immediately but is limited in its duration to the time that protective levels of antibodies remain in the circulation see also Chapter 16. 

Immune sera are sterile solutions containing antibody derived from human (immune globulin [IG]) or equine (antitoxin) sources. 

Abzyme An alternative name for a catalytic antibody (derived from Antibody-enzyme). 

Monoclonal antibody, mAb Describes an antibody derived from a single clone of cells or a clonally obtained cell line. Its common use denotes an antibody secreted by a hybridoma cell line. Monoclonal antibodies are used very widely in the study of antigens, and as diagnostics. 

Polyclonal antibodies Antibodies derived from a mixture of cells, hence containing various populations of antibodies with different amino add sequences. They are of limited use in that they will not all bind to the same epitopes following immunization with a haptenlcarrier protein conjugate. They are also difficult to purify and characterize, but have been used with success in the catELISA system. 

Antibodies Derived from Horse Antisera Botulism antitoxin, diphtheria antitoxin, scorpion venom antisera, snake venom antisera, spider anti-venins, and tetanus antitoxin. 

Antibodies Derived from Human Donors Hepatitis A and B immunoglobulins, measles immunoglobulins, rabies immunoglobulin, and tetanus immunoglobulin. 

In 1994, the Dako Corporation introduced its Envision system (10). This immunoenzyme technique achieves both sensitivity and speed in a universal reagent. The secondary antibodies (derived from goats, in the case of the per-... 

Whole IgG antibodies with a molecular weight of 150 kDa, are often unable to penetrate tumour tissue as efficiently as smaller molecules [18]. Therefore, smaller antibody fragments and genetically-engineered antibody derivatives have been investigated as drug carriers (see Figure 11.5). These carrier molecules will be discussed in Section 11.8.1. 

Antibodies derived from human serum not only avoid the risk of hypersensitivity reactions but also have a much longer half-life in humans (about 23 days for IgG antibodies) than those from animal sources (5-7 days or less). Consequently, much smaller doses of human antibody can be administered to provide therapeutic concentrations for several weeks. 

In summary, only a few therapeutic polyclonal antibodies are still marketed today. The main advantages of mAbs are their high specificity towards the target and the capability of an unlimited production of these homogeneous biological molecules. In future, new antibody or antibody-derived pharmaceuticals will be developed and can be expected to have favorable efficacy, a lack of immunogeni-city, and appropriate pharmacokinetics such that they can be used to treat intracellular medical disorders. 

In the following, the four most important and best-understood effector functions/ modes of action of therapeutic mAbs or antibody-derived products (e. g., antibody fragments) will be discussed, and will focus on cancer therapy. The different modes of action of mAbs in cancer therapy are depicted in Fig. 3.4. As this topic is not entirely within the scope of this chapter, the reader is referred to textbooks on immunology for more details on the modes of action of mAbs. 

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