An Enzyme-Linked Immunosorbent Assay for Quantifying Adherence of Candida to Human Vascular Endothelium

Abstract

Success in elucidating the pathogenesis of certain bacterial infections through studies of bacterial adherence to host cells has stimulated interest in parallel investigations of fungal adherence. Fungal adherence differs from bacterial adherence, especially when fungal coadherence (adherence of fungal cells to each other) is a factor. Using human umbilical vein endothelial cells cultured in a living monolayer in microtiter plates, we developed an ELISA to study adherence of Candida albicans to endothelial cells in the absence of yeast coadherence. A rabbit antibody to Candida detected the adherent Candida, and an alkaline phosphatase-conjugated antibody to rabbit IgG was the developing antibody. A linear relationship between the log of the optical density and the log of the number of adherent organisms was seen for wells containing 3 × 10⁴-1 × 10⁶ organisms (r = .923- .965). In addition to measuring adherence of living Candida to living target cells and avoiding Candida coadherence, this assay makes it possible to investigate adherence limited to lumenal surfaces, conserves reagents, and facilitates the testing of large numbers of potential adherence modifiers.