Antigenemia detected by enzyme-linked immunosorbent assay in rabbits with systemic candidiasis.

To aid in the rapid, accurate, and early diagnosis of systemic and invasive Candida infections, a double-antibody sandwich enzyme-linked immunosorbent assay was developed for the detection of circulating Candida antigens. The sensitivity for purified mannan was 0.1 to 1 ng/ml. No reactivity was seen with a variety of other fungal and bacterial antigen preparations. The assay was evaluated in normal or immunosuppressed rabbits with varying degrees of systemic candidiasis. All rabbits given infecting doses of 10(7) or 10(8) organisms were positive for Candida antigens with increasing titers until death. Rabbits given 10(6) organisms were variably and transiently positive. All control infected and uninfected rabbits were negative. This sensitive and specific technique detects Candida antigens in the serum of infected rabbits before widespread organ involvement occurs and should prove extremely valuable in the early diagnosis of systemic candidiasis.