Immunization adjuvant preparation

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. 

Adjuvants are substances which can modify the immune response of an antigen (139,140). With better understanding of the functions of different arms of the immune system, it is possible to explore the effects of an adjuvant, such that the protective efficacy of a vaccine can be improved. At present, aluminum salt is the only adjuvant approved for use in human vaccines. New adjuvants such as QS-21, 3D-MPL, MF-59, and other liposome preparations are being evaluated. Several of these adjuvants have been in clinical trial, but none have been approved for human use. IL-12 has been proposed as an adjuvant which can specifically promote T-helper 1 ceU response, and can be a very promising adjuvant for future vaccine development. 

The adjuvant effect of different doses of lipid A in lipospheres was also examined by immunizing rabbits with lipospheres containing R32NS1 and prepared at different final concentrations of lipid A. The ELISA titers of the individual rabbit groups immunized, as determined by dilution of serum obtained at 6 weeks after primary immunization, have shown a gradual increase in IgG antibody titer with increasing... 

Antibody Production A thick emulsion of the immunogen (clonazepam-bovine-serum-albumin-con-jugate) is prepared employing complete Freund s adjuvant and two New Zealand white female rabbits are immunized intradermally at multiple sites with the immunogen emulsion. The animals are then administered... 

Polyclonal antibodies are produced by injecting an antigen into an animal in the presence of an adjuvant containing bacterial lipopolysaccharides that stimulate the immune system. Serum prepared from the blood contains several different classes of antibodies that interact with different domains in the antigen molecule, each of... 

Finally, besides conventional liposomes that are made from natural (e.g., egg yolk and soybean) or synthetic phospholipids, novel liposomes called archaeosomes that are prepared from the polar ether lipids extracted from various archaeobacteria proved also interesting for the design of vaccines as peptide antigen carriers (71) and as powerful self-adjuvanting vaccine delivery vesicles that promote both humoral and cell-mediated immunity (72). Related to this, one can mention that pseudopeptides, which are less prone to proteolysis when conjugated to liposomes, were also competent in triggering a humoral immune response (73). 

Successful vaccines have several important properties such as safety, effectiveness, low cost per dose, and ease of preparation. Vaccines, whether peptide, protein, or DNA, have limited potency without codelivery with an adjuvant and/or a specialized delivery system (11). There is currently a lack of safe, nontoxic, effective. Food and Drug Administration (FDA)-approved vaccine adjuvants capable of stimulating cellular (Thl) immunity (12). Most potent immune activators are also toxic at relatively low doses and cannot, therefore, be successfully used as adjuvants (12). 

Fig. 1. Preparation of emulsion for immunization. Two iuer Jock glass syringes connected by a three-way plastic stopcock are used to form a stable emulsion of antigen and adjuvant.

Adjuvants stabilize immunogens so that they induce the immune system persistently over long periods. Oil-water adjuvants, such as Freund s, are extremely effective, but must be prepared properly as stable emulsions. Such emulsions are thick, do not separate even after standing for long periods, and do not disperse if pipeted onto the surface of water. Immunogens administered in Freund s adjuvant can persist for weeks, and there is thus no point in repeating... 

Three weeks after the first injection, immunize the animal subcutaneously The emulsion is prepared m the same quantity and in the same way as before, but instead of Freund s complete adjuvant, use Freund s incomplete adjuvant (or an alternative adjuvant of the new generation of adjuvants)... 

BCG is a viable strain of Mycobacterium bovis that has been used for immunization against tuberculosis. It has also been employed as a nonspecific adjuvant or immunostimulant in cancer therapy but has been successful only in intravesical therapy for superficial bladder cancer. BCG appears to act at least in part via activation of macrophages to make them more effective killer cells in concert with lymphoid cells in the cellular efferent limb of the immune response. Lipid extracts of BCG as well as nonviable preparations of Corynebacterium parvum may have similar nonspecific immunostimulant properties. A chemically defined derivative of the BCG cell wall, [Lys18]-muramyl dipeptide, has been licensed in Japan to enhance bone marrow recovery after cancer chemotherapy. 

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