High Quality Content by WIKIPEDIA articles! Freund`s adjuvant is a solution of antigen emulsified in mineral oil and used as an immunopotentiator (booster). The complete form, Freund`s Complete Adjuvant,(CFA or FCA) is composed of inactivated and dried mycobacteria (usually M. tuberculosis), whereas the incomplete form (IFA or FIA) lacks the mycobacterial components (hence just the water in oil emulsion). It is named after Jules T. Freund.