The water-in-oil emulsion adjuvants developed by Jules Freund and cowo
rkers have been, and continue to be, used in research and veterinary v
accines. Incomplete Freund's Adjuvant (IFA) has also been widely teste
d in humans where it was shown to augment antibody responses greater t
han other adjuvants, such as alum, and to be well tolerated. Toxicity
associated with the use of IFA has been controlled by the use of high
grade oils and purified surfactants and clinical testing is ongoing to
day. One potential limitation of IFA is that it does not augment the
types of cellular immune responses that thought to be critical to the
control of many viral infections and tumors. However, IFA can be mixed
with or used in conjunction with other adjuvant-active compounds, suc
h as saponins and cytokines. These mixed formulations or vaccine proto
cols have proved successful in animal testing and may soon be tested i
n clinical trials. Thus, the toxicity and potential limited adjuvant a
ctivity of IFA can be controlled or corrected making IFA a useful prod
uct in the vaccine industry. (C) 1998 Elsevier Science B.V.