Freund's adjuvant

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The Freund's adjuvant , as Freund's adjuvant , formerly Freund's adjuvant referred to is a water-in- oil - emulsion , the killed micro-organisms ( Mycobacterium tuberculosis contains). It is an auxiliary substance ( adjuvant ) used in research that strengthens the desired immune reactions of an experimental animal and is still often used for immunizations (as a complete Freund's adjuvant, CFA), although this is rejected by animal rights activists due to the side effects.

It was developed by Jules T. Freund and Katherine McDermot

Complete Freund's adjuvant

Freund's Complete Adjuvant (CFA) contains three essential components:

  1. Mineral oil ( paraffin oil ) that cannot be metabolized and thus ensures a depot effect
  2. heat-inactivated mycobacteria , which are responsible for the strong stimulation of the immune system; typically 1 mg / ml.
  3. Arlacel A as an emulsifier to keep the water-in-oil emulsion stable.

In order to achieve the desired effect, careful preparation of the emulsion is essential. The KFA that is to be used must be mixed very well in order to allow the mycobacteria to be evenly distributed. Portions of water are then added to ensure that the oily phase remains the determining factor. The resulting emulsion is mixed well every time; this happens until a ratio of 1: 1 (oil: water) is reached. The goal is to keep water droplets small enough and not to provoke air pockets. If this is achieved, a drop of the emulsion applied to a cold water surface retains its coherence (its cohesion).

Incomplete Freund's adjuvant

The incomplete Freund's adjuvant (IFA) dispenses with the addition of mycobacteria and is / was used for subsequent injections to strengthen ( boost ) the immune response after the first injection with KFA.

advantages and disadvantages

Freund's adjuvant is still one of the most powerful adjuvants for triggering an immune response. An example: How can one experimental autoimmune encephalomyelitis (EAE) by the injection of peptides of myelin (MBP, PLP, MOG, MAG) in complete Freund's adjuvant and enhancing the immune response to cell wall constituents of Mycobacterium tuberculosis (or pertussis ) are triggered - and Ultimately, the mechanisms that lead to the development of multiple sclerosis - a disease that has so far eluded a complete explanation of the pathogenesis - will be researched. Nonetheless, effective drugs (such as glatiramer acetate ) for this condition can be developed, a process that in this case took more than 30 years.

Due to its inflammation-promoting properties, the formation of abscesses - especially when introduced into the muscles ( intramuscular injection ) - and granulomas are to be expected. When administered into the abdominal cavity ( intraperitoneal application ) - usually in mice and rats - peritonitis is caused. These side effects depend on the amount of adjuvant introduced, the concentration of the antigen and the quality of the adjuvant produced.

Researchers and animal rights activists were able to come to an agreement, at least in some places, to ban some types of administration, for example in 1997 with the “List of animal experiments no longer permitted at Zurich universities”. In this way, the plantar immunization with KFA (in the balls of the feet) and its intraperitoneal administration, and the intraperitoneal injection of strongly irritating substances to obtain peritoneal macrophages in general, were abolished.

The intravenous application can lead to death of the animal, so that the recommended application to a subcutaneous or intradermal limited application.

Instead, oil formulations are administered for the initial vaccination and their replacement with aluminum hydroxide gel is recommended for subsequent injections , since equivalent results can be achieved with less exposure to the test animals.

literature

Individual evidence

  1. ↑ a b Werner Nicklas, Klaus Cußler, Joachim Hartinger: Animal welfare aspects in the immunization of test animals: Leaflet No. 4. (PDF; 57 kB) Veterinary Association for Animal Protection eV, 1997, accessed on July 23, 2017 .
  2. ^ A b W. C. Hanly, B. Taylor Bennett, James E. Artwohl: Overview of Adjuvants: Advantages and disadvantages of Freund's adjuvants. In: barbfeick.com. 1994, accessed July 23, 2017 .
  3. ↑ Susanne Wolf: Neurodegeneration and Neuroprotection - a dialogue between the immune system and the brain at the cellular level . Berlin 2001, DNB  963815083 , urn : nbn: de: kobv: 11-10016374 (dissertation, Humboldt University Berlin).
  4. ↑ Volker Dietz, Hans M. Eppenberger, Dieter Glaser, Antoine F. Goetschel, Klaus W. Grätz, Franz P. Gruber, Irène Hagmann, Marie-Claude Hepp-Reymond, Walter Lichtensteiger, Hans Lutz, et al .: List no more permitted animal experiments at Zurich universities . In: ALTEX . tape 14 , no. 2 , 1997, ISSN  1868-596X , p. 61–62 ( PDF - free full text).
  5. ↑ Katja Jansen: Methodical studies on the properties, detection, purification and antigenicity of the α-toxin of Clostridium septicum . Göttingen 2000, DNB  961183098 , urn : nbn: de: gbv: 7-webdoc-895-0 (dissertation, University of Göttingen).