Polyclonal antibody preparation

Polyclonal antibody preparations have been used for several decades to induce passive immunization against infectious diseases and other harmful agents, particularly toxins. The antibody preparations are usually administered by direct i.v. injection. While this affords immediate immunological protection, its effect is transitory, usually persisting for only 2-3 weeks (i.e. until the antibodies are excreted). Passive immunization can be used prophylactically (i.e. to prevent a future medical episode) or therapeutically (i.e. to treat a medical condition that is already established). An example of the former would be prior administration of a specific antisnake toxin antibody preparation to an individual before he/she travelled to a world region in which these snakes are commonly found. An example of the latter would be administration of the anti-venom antibody immediately after the individual has experienced a snake bite. 

Antibody preparations used to induce passive immunity may be obtained from either animal or human sources. Preparations of animal origin are generally termed antisera , while those sourced from humans are called immunoglobulin preparations . In both cases, the predominant antibody type present is immunoglobulin G (IgG). 

Biopharmaceuticals Biochemistry and Biotechnology, Second Edition by Gary Walsh John Wiley Sons Ltd ISBN 0 470 84326 8 (ppc), ISBN 0 470 84327 6 (pbk) 

The blood is collected using aseptic technique into sterile containers. It can then be allowed to clot, with subsequent recovery of the antibody-containing antisera by centrifugation. Alternatively, the blood may be collected in the presence of heparin, or another suitable anticoagulant, with subsequent removal of the suspended cellular elements, again by centrifugation. In this case, the resultant antibody-containing solution is termed plasma . 

As is the case with all other pharmaceutical substances, all aspects of antisera production must be undertaken by means conducive to the principles of GMP. Most regulatory authorities publish guidelines which outline acceptable standards/procedures for the production of such blood-derived products. Donor animals must be healthy and screened for the presence of (particularly blood-borne) pathogens. They must be housed in appropriate animal facilities, and withdrawal of blood must be undertaken by aseptic technique. Subsequent downstream processing must be undertaken according to the principles of GMP, as laid down in Chapter 3. 

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Immunoassays employ monoclonal or polyclonal antibody preparations (Chapter 13) to detect and quantify the product (Box 7.1). The specificity of antibody-antigen interaction ensures good assay precision. The use of conjugated radiolabels (RIA) or enzymes (EIA) to allow detection of antigen-antibody binding renders such assays very sensitive. Furthermore, when compared with... 

Polyclonal antibody preparations have been used to induce passive immunity against a range of foreign (harmful) agents, and vaccines are used efficiently, and safely, to promote active immunization. Adjuvants are usually co-administered with the vaccine preparation, in order to enhance the immune response against the vaccine. 

The major polyclonal antibody preparations used therapeutically are listed in Table 13.1. These may generally be categorized into one of several groups upon the basis of their target specificities. These groups include antibodies raised against ... 

Table 13.1 Polyclonal antibody preparations of human or animal origin used to induce passive immunity against specific biological agents...

Polyclonal antibody preparations raised against toxins of poisonous snakes and spiders (i.e. venins), are used in the medical management of individuals who have suffered bites from these creatures. In many instances immediate administration of the appropriate antiserum can prevent almost certain death. 

Table 10.2. Some polyclonal antibody preparations raised in horses against specific snake toxins...

Since polyclonal antibodies recognize a variety of epitopes on the antigen, they generally work well in the technique of immunoprecipitation (see below). Many polyclonal antibody preparations have also proven to be effective in the techniques of... 

Since monoclonal antibodies recognize a particular epitope on the antigen, they tend to be less cross-reactive than polyclonal antibodies in Western blotting and ELISAs. Also, because the interaction takes place with a defined affinity (dissociation constant), monoclonal antibodies are frequently preferred in the technique of im-munoaffinity chromatography (see Introduction to Experiment 2). The wide variety of antigen-antibody interactions that are present in a polyclonal antibody preparation makes it difficult to define a mobile-phase buffer that will promote the elution of the antigen of interest in good yield from an im-munoaffinity column prepared with polyclonal antibodies. 

The free amide peptide was synthesized on 4-methylbenzhydrylamine-substituted polystyrene resin, and the resin-bound peptide for antibody production was prepar on aminomethyl polystyrene. Cleavage/deprotection was done with hydrogen fluoride/anisole at 0 C. The free amide was not active in either bioassay. However, polyclonal antibody prepared against the resin-bound (22 24) sequence was immunologically reactive to EDNH reverse phase column fractions. We are now attempting to determine if the sequence represents an inactive fragment of authentic EDNH. 

Exposure to a specific antigen causes clonal expansion of all B cells capable of reacting with the multiple epitopes present on the antigen. Thus, the immune response to the entire antigen results in the production of antibodies by several clones of B cells. The resultant mixture of antibodies present in the serum is called a polyclonal antibody. In addition, because an animal is naturally exposed to a host of other antigens in its environment, its serum also contains antibodies produced by clones specific for each of these antigens. Therefore a polyclonal antibody preparation obtained from an animal is a mixture of many distinct antibody classes, only some of which are specific for the antigen used in experimental immunization. 

The properties of the H. salinarium halobium) enzyme are those expected of a V-type ATPase. Polyclonal antibodies prepared against the H. salinarium halobium) ATPase react with the two largest subunits from the ATPases from S. acidocaldarius and beet root tonoplast, but fail to react with the subunits from chloroplast F-ATPase [87]. This result contradicts the observation that polyclonal antiserum against the 3 subunit from S. acidocaldarius, which reacts with various 3 subunits from F-type ATPases, reacts with subunit II from H. saccharovorum and a M, 67000 subunit from the H. salinarium halobium) ATPase [60]. 

Two polyclonal antibody preparations have been prepared according to the method outlined in this chapter. The preparations were tested for antibody concentration by measuring their titer. Preparation A possesses a titer of 1 1024, while preparation B has a titer of 1 128. Which is the more concentrated preparation of antibodies ... 

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