Vaccine Adjuvants

Freund's adjuvant

Jules T Freund

It is an w/o emulsion made from (i) aqueous phase - a solution of antigen, (ii) oil-phase - mineral oil and (iii) an emulsifier - Arlacel A (Dianhydro-D-mannitol monooleate). When this emulsion was injected in animal it was found to act as an immunopotentiator or booster to immunity reaction.

Complete Freund's Adjuvant (CFA or FCA)

It is composed of inactivated and dried mycobacteria (usually M. tuberculosis) which acts as the antigen. The antigen is administered in the form of w/o emulsion.

• CFA stimulates the cell-mediated immunity. It potentiates the T-helper cells that lead to the production of certain immunoglobulins and effector T-cells.
• The CFA is very toxic to animals and human beings as well. It produces painful reaction and causes tissue damages (necrosis). 
• FCA should be administered subcutaneously or intraperitoneally because intradermal injections may cause skin ulceration and necrosis, intramuscular injection may lead to permanent muscle lesion and intravenous injections may produce lipid embolism.

Incomplete Freund's Adjuvant

The w/o emulsion is devoid of any antigen, i.e. it is the emulsion only.

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