Freund’s Complete Adjuvant Test

Feature of test Draize Open Epicutaneous Tests (OET) Beuher Assay Freund s Complete Adjuvant Test (FCA) Optimization Test Split Adjuvant Guinea Pig Maximization (GPMT)... 

Klecak G (1983) Identification of contact allergens Predictive tests in animals. In Marzulli FN, Maibach HI (eds) Der-matotoxicology. Hemisphere, New York, pp 193-236 Klecak G (1985) The Freund s Complete Adjuvant Test and the Open Epicutaneous Test. A complementary test procedure for realistic assessment of allergenic potential. Curr Probl Dermatol 14 152-171... 

Freund s complete adjuvant test Maximization test Open epicutaneous test... 

The guinea pig maximization test (GPMT) is a preferred method for the detection of skin sensitizers. It belongs to the class of adjuvant-tests, where the substance will be applied in Freund s complete adjuvant (FCA). The test is based on the possible induction of an immune response of the skin during an induction period (at least 1 week). This pretreatment of the subject will eventually result in a hypersensitive reaction during a further exposure, the so-called challenging phase. 

There are a number of models for detecting allergic contact dermatitis in guinea pigs. The maximisation test developed by Magnussun and Kligman is the most widely used and employs both an intradermal and topical sensitisation phase, together with the non-specific stimulation of the immune system by the intradermal injection of Freund s complete adjuvant. 

When rabbits were immunized with the glycoconjugates suspended in Freund s complete adjuvant antibodies with specificity for the haptenic disaccharides were produced, as estimated in passive hemagglutination and complement-mediated bactericidal tests, and enzyme-linked immunosorbent assay (ELISA) (12-15). 

FCA - Freund s complete adjuvant SLS - sodium lauryl sulfate TS - test substance V - vehicle id - interdermal. Reproduced from Maibach and Patrick (2001) with permission. 

Four rabbits were used for immunizations with vaccine of equal parts of nonviable cells of S. faecalis suspension and Freund s complete adjuvant. Each week the rabbits are injected intravenously with 0.2 mL of the vaccine for 3 consecutive days, followed by a rest period of 4 days. This regime is performed for 5 weeks and is followed by a 1-week rest period. The immunization is performed in the same manner as before for 6 more weeks. Blood samples are drawn weekly after the fourth week of initial immunization. The serum is separated and tested by agar diffusion for the presence of antibodies. 

The presence of heat-killed mycobacteria in Freund s complete adjuvant serves to generally stimulate the entire reticuloendothelial system of the test animal. In addition, there is some evidence these dead celts also stimulate T lymphocyte proliferation and their production of B cell-stimulating factors. Use of the complete adjuvant is recommended for the first dose of immunogen but incomplete adjuvant is adequate for subsequent injections. 

Sensitization assays involve mixing the material or extract that has been in contact with a device with Freund s complete adjuvant and injection of the test sample into the subcutaneous tissue during a 2-week induction period (37). After 2 weeks, the material or extract is placed on the skin near the injection site for 24 hours, and then the skin is evaluated for redness and swelling. 

Intradermal injection of 0.1 ml each of a water-in-oil type emulsion (E-FCA/distilled water Freund s complete adjuvant 1 1) into the 4 corners of shoulders of test animals. 

The technique described by Floersheim is as follows. Guinea-pigs are sensitized by the subcutaneous administration of BCG vaccine in Freund s complete adjuvant. An intradermal injection of tuberculin 4-8 weeks later, elicits a typical erythematous reaction which is evaluated by measuring the degree of infiltration, the area of erythema and its intensity 8 and 24 hours after the tuberculin injection. Drugs under test are given 30 minutes before and 8 hours after the tuberculin. 

Typical protocols for dermal sensitization, active systemic anaphylaxis, and passive cutaneous anaphylaxis tests are given in the article Animals in Drug Development, in this encyclopedia. In a typical gel-diffusion test, solutions of test compound, egg albumin (positive control), or vehicle (usually saline) are mixed with complete Freund s adjuvant. These mixtures are injected into animals (usually guinea pigs) of the... 

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