Polypeptides smaller than 10 kDa and non-protein
antigens usually need to be conjugated to a carrier protein to
become good immunogens. Additionally these, as well as other
protein antigens, need to be administered with an adjuvant to
ensure a high quality/quantity response. This is especially true if
low levels of antigen are to be administered. There are a number of
adjuvants that are available for use in polyclonal antibody
production. Complete Freund’s adjuvant continues to be the most
commonly used despite its potential hazards.
In order to eliminate or reduce discomfort, national guidelines
may require adequate justification for the use of Complete
Freund’s. Below is a list of adjuvants and their properties. This
should allow you to make an informed choice on the adjuvant most
suited to your project’s needs. The adjuvant of choice needs to be
filled out on the
Antibody Services Production Questionnaire:
Freund’s Complete
Adjuvant (FCA)
- FCA is a mixture of a non-metabolisable oil (mineral oil), a
surfactant (Arlacel A), and mycobacterium (M.tuberculosis or M.
butyricum). It is prepared as an oil in water emulsion. In the
emulsion, antigen is distributed over a large surface area, thereby
increasing the potential for interaction within relevant cells.
Antibody production is enhanced using FCA because of the depot
effect and non-specific immuno-potentiation of macrophages by
surfactant and mycobacterium. FCA has been found to cause
inflammation, necrosis and discomfort and therefore, if use is
justified, it is limited to the primary immunisation only.
Freund’s Incomplete
Adjuvant
- This adjuvant has the same oil/surfactant mixture as FCA but
does not contain any mycobacterium. It is frequently used as a
booster injection but can be used for the primary injection as
well. Its properties favour humoral immunity responses rather than
cell mediated responses. Less severe reactions are seen than with
FCA.
Hunter’s
Titermax
- This is an oil/surfactant-based adjuvant, prepared in a similar
manner to FCA, except it uses a metabolisable oil and a non-ionic
surfactant that has good protein antigen binding capacity as well
as adjuvant activity. It has been found to be superior or equal to
FCA with some protein antigens, particularly in rabbits and mice,
although not so successful in rats. Smaller quantities of titermax
are required for initial injections minimising the inflammatory
reaction. Booster injections may be needed less frequently than
with FCA.
Gerbu
Adjuvant
- A new aqueous phase adjuvant that does not have a depot effect.
It utilises immuno-stimulators in combination with zinc proline.
Although it requires frequent boosting to achieve a high-titre
response, the inflammatory effect is minimal and has been shown to
be safe for intra-muscular injections in rabbits.
Ribi’s
Adjuvants
- Ribi’s Adjuvants are mixtures of oil, detergent and
immunostimulators. To minimise inflammatory response the adjuvant
utilises a metabolisable oil and contains modified bacterial
products. The depot effect is not as great as with FCA so more
frequent booster injections are needed. Ribi’s may not be
applicable to all antigens or species but may, insome cases, be
superior to FCA. In general, Ribi’s adjuvant emulsion is better for
protein antigens that have some hydrophobic aspects than for very
hydrophilic proteins. This biases the antibody response to epitopes
of the native protein rather than to epitopes of the denatured
protein.
Contact us at antibodies@harlan.com for
pricing and additional information.